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Abatement :

Reduction of the degree or intensity of, or elimination of pollution.

Abridged Life Cycle Assessment (ALCA) :

A simplified methodology to evaluate the environmental effects of a product or activity holistically, by analyzing the most significant environmental impacts in the life cycle of a particular product, process, or activity. The abridged lifecycle assessment consists of three complimentary components, restricted inventory analysis, abridged impact assessment, and improvement analysis, together with an integrative procedure known as "Scoping."

Absolute Pressure :

The sum of the gauge pressure reading and atmospheric pressure.

Absorption :

Process by which a substance or particle is drawn into the structure of another.

Acetone :

A colorless, volatile, extremely flammable liquid ketone, CH3COCH3, widely used as an organic solvent.

Acid Deposition :

The deposition of acid constituents to a surface. This occurs not only through precipitation, but also by the deposition of atmospheric particulate matter and the incorporation of soluble gases.

A cid Rain :

The precipitation of dilute solutions of strong mineral acids, formed by the mixing in the atmosphere of various industrial pollutants (primarily sulfur dioxide and nitrogen oxides) with naturally occurring oxygen and water vapor.

Acrylics :

A family of plastics used for fibers, rigid sheets and paints.

Active Diffuser :

An air supply outlet with a local fan to deliver air from the plenum through the diffuser into the conditioned space.

Active Solar Techniques :

Mechanisms, such as flat-plate collectors, which are designed to actively collect the energy of sunlight and use it; for example, to heat a building or to heat water.

A ctive System :

A traditional HVAC system that uses mechanical means to artificially condition (cool, heat, ventilate) the air supply in a building and that draws power for these processes from electricity or gas.

Active Solar Heating :

Heat from the sun is absorbed by collectors and mechanically transferred by pumps or fans for storage for heating, cooling, or making electricity.

Acute Exposure :

A single exposure to a toxic substance that may result in severe biological harm or death. Acute exposures are usually characterized as lasting no longer than a day, as compared to longer, continuing exposure over a period of time.

Acute Toxicity :

The ability of a substance to cause severe biological harm or death soon after a single exposure or dose. Also, any poisonous effect that results from a single short-term exposure to a toxic substance.

Adaptive Reuse :

Renovation of a building or site to include elements that allow a particular use or uses to occupy a space that originally was intended for a different use.

Adsorbent :

Material that is capable of the binding and collection of substances or particles on its surface without chemically altering them.

Adsorption :

Removal of a pollutant from air or water by collecting the pollutant on the surface of a solid material.

Advanced Treatment :

A level of wastewater treatment more stringent than secondary treatment; requires an 85% reduction in conventional pollutant concentration or a significant reduction in non-conventional pollutants. Sometimes called tertiary treatment.

AEE (Association of Energy Engineers) :

A trade organization for certification and information on energy efficiency, utility deregulation, facility management, plant engineering, and environmental compliance.

Aeration :

Exposing water to the air; often results in the release into the atmosphere of gaseous impurities found in polluted water.

Aerobic Treatment :

Process by which microbes decompose complex organic compounds in the presence of oxygen and use the liberated energy for reproduction and growth.

Aerosol :

Suspended droplets of liquid or liquid dispersions in air.

Agenda 21 :

A comprehensive blueprint for global action drafted by the 172 governments present at the 1992 Earth Summit organized by the United Nations in Rio de Janeiro, Brazil.

Agricultural Bi-products :

Products developed in agriculture but are not primary products. These are often converted into building materials, such as straw used in wall panels or entire bales used as building blocks.

Agricultural Fibers :

Natural fibers, such as cotton, often used as insulation materials.

Air Barrier :

Material that is installed around a building frame intended to reduce the infiltration of air into the interior.

Air Change :

The replacement of air contained within a room with an equivalent volume of fresh air.

Air Change Effectiveness (ACE) :

The ability of an air distribution system to provide ventilation (outside) air at the breathing zone (where occupants breathe). It is defined as the age of air that would occur throughout the space if the air was perfectly mixed, divided by the average age of air where occupants breathe.

Air Changes Per Hour (ACH) :

Number of times per hour a volume of air, equivalent to the volume of space, enters that space.

Air Cleaner :

A filtering device that actively removes impurities from the air.

Air Conditioning (A/C) :

A system that extracts heat from an area using a refrigeration cycle. A complete system of heating, ventilation, and air conditioning is referred to as HVAC. See "Heating, Ventilating and Air Conditioning."

Air Conditioning and Refrigeration Institute (ARI) :

A trade association (representing manufacturers of more than 90 percent of the air conditioning and commercial refrigeration equipment installed in North America) that develops standards for and certifies the performance of these products.

Air Consumption :

The volume of air required to operate a pneumatic device.

Air Exchange Rate :

The rate at which outside air replaces indoor air in a given space. Also see "Air Changes per Hour."

Air Flow :

The movement of air within a room, duct, or plenum.

Air Flow Sensor :

A device that measures air velocity (via differential pressure) inside a duct.

Air Handling Unit (AHU) :

Equipment that includes a fan or blower, heating and/or cooling coils, regulator controls, condensate drain pans, and air filters.

Air Inlet :

Apertures (grilles, diffusers, or louvered openings) through which air is intentionally drawn from a conditioned space.

Air Outlet :

Apertures, (grilles, diffusers, or louvered openings) through which air is intentionally delivered to a conditioned space.

Air Plenum :

Any space used to convey air in a building, furnace or structure. The space above a suspended ceiling is often used as an air plenum.

Air Quality Standards :

The level of pollutants prescribed by regulations that are not to be exceeded during a given time in a defined area.

Air Supply Volume :

The volume of supply air flowing through a cross-sectional plane of a duct per unit time, found by multiplying air velocity by the cross-sectional area of the duct.

Air Exchange Rate :

The rate at which outside air replaces indoor air in a given space.

Air Handling Unit :

Equipment that includes a fan or blower, heating and/or cooling coils, regulator controls, condensate drain pans, and air filters.

Air Plenum :

Any space used to convey air in a building, furnace or structure. The space above a suspended ceiling is often used as an air plenum.

Air Pollutant :

Any substance in air that could, in high enough concentration, harm man, other animals, vegetation or material. Pollutants may include almost any natural or artificial composition of matter capable of being airborne. They may be in the form of solid particles, liquid droplets, gases or any combination thereof. Air pollutants are often grouped in categories for ease in classification. Some of these categories are solids, sulfur compounds, volatile organic chemicals, particulate matter, nitrogen compounds, oxygen compounds, halogen compounds, radioactive compounds and odors.

Air Pollution :

The presence of contaminants or pollutant substances in the air that interfere with human health or welfare, or produce other harmful environmental effects.

Air Toxics :

Any air pollutant for which a National Ambient Air Quality Standard (NAAQS) does not exist that may reasonably be anticipated to cause serious or irreversible chronic or acute health effects in humans.

Airborne Particulates :

Total suspended particulate matter found in the atmosphere as solid particles or liquid droplets. Chemical composition of particulates varies widely, depending on location and time of year. Sources of airborne particulates include dust, emissions from industrial processes, combustion products from the burning of wood and coal, combustion products associated with motor vehicle or non-road engine exhausts, and reactions to gases in the atmosphere.

Albedo :

A reflective property of a surface.

Allergen :

A substance (also known as an antigen) that can trigger immune responses resulting in an allergic reaction.

Alternative Energy :

Energy from a source other than the conventional fossil-fuel sources of oil, natural gas and coal (i.e., wind, running water, the sun). Also referred to as "alternative fuel."

Alternative Energy Sources :

Energy sources, which can be substituted for fossil fuels, nuclear power, and large-scale hydroelectric power; e.g., solar, wind, geothermal, biomass.

Alternative Fuels :

similar to alternative energy. Not fossil fuels, but different transportation fuels like natural gas, methanol, bio fuels and electricity.

Ambient Air :

The surrounding air.

Ambient Temperature :

Temperature of the surrounding air or other medium.

American National Standards Institute :

See "ANSI."

American Society of Heating, Refrigerating and Air-Conditioning Engineers :

See "ASHRAE."

Annual Consumption :

Annual consumption refers to the amount of electricity used by a consumer in one year and is typically measured in kilowatt-hours (kWh). This information is available on your electricity bill or by contacting your energy provider.

Annual Fuel Utilization Efficiency (AFUE) :

(AFUE) Seasonal efficiency of a gas-fired furnace or boiler. Takes into account cyclic operation. The higher the number, the more efficient the heating equipment.

Annual Fuel Utilization Efficiency (AFUE) :

A measure of efficiency for gas furnaces and boilers, the ratio of annual output energy to annual input energy.

ANSI (American National Standards Institute) :

A private nonprofit organization overseeing the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international standards so that American products can be used worldwide.

Anthropogenic :

Derived from human activities.

Antigen :

See "Allergen."

Antimicrobial :

An agent that kills microbes.

Aquifer :

Any underground water-bearing rock formation or group of formations, that supplies ground water, wells, or springs.

ARI :

See "Air Conditioning and Refrigeration Institute."

Asbestos :

A mineral fiber that can pollute air or water and cause cancer or asbestosis when inhaled. The EPA has banned or severely restricted its use in manufacturing and construction.

Asbestos Abatement :

Procedures to control fiber release from asbestos-containing materials in a building or to remove them entirely, including removal, encapsulation, repair, enclosure, encasement, and operations and maintenance programs.

ASHRAE :

American Society of Heating, Refrigeration and Air Conditioning Engineers. A world-wide organization that promotes the arts and sciences of heating, ventilation, air conditioning, and refrigeration and that publishes standards. Particularly important in relationship to green building construction is ASHRAE 90.1 Energy Standard for Buildings except Low-Rise Residential Buildings, a code setting requirements for energy efficiency and methods of determining compliance.

ASHRAE Standard 62 :

Ventilation for Acceptable Indoor Air Quality. Details two methods for compliance:

Ventilation Rate Procedure and the Indoor Air Quality Procedure. Rapidly becoming the standard of care for building ventilation and indoor air quality.

Atmospheric Pressure :

The pressure due to the weight of the atmosphere (14.7 PSI at sea level).

Attainment Area :

An area considered to have air quality as good as or better than the national ambient air quality standards as defined in the Clean Air Act. An area may be an attainment area for one pollutant and a non-attainment area for others.

Backdrafting :

Potentially hazardous condition in which the exhaust from combustion appliances does not properly exit the building. This can be due to a number of factors including a blocked flue or a pressure difference within the home.

BACT-Best Available Control Technology :

An emission limitation based on the maximum degree of emission reduction (considering energy, environmental and economic impacts) achievable through application of production processes and available methods, systems and techniques. BACT does not permit emissions in excess of those allowed under any applicable Clean Air Act provisions. Use of the BACT concept is allowable on a case-by-case basis for major new or modified emissions sources in attainment areas and applies to each regulated pollutant.

Bake-out :

Process by which a building is heated in an attempt to accelerate VOC emissions from furniture and materials.

Bakeout :

A technique for reducing the exposure of occupants to emissions of new construction. The building temperature is raised to a high level (to enhance emissions of volatile compounds from new materials) for several days before occupancy, while running the ventilation system at full capacity to exhaust the emissions.

Balance Point :

The outdoor temperature at which a building's heat loss to the environment is equal to internal heat gains from people, lights, and equipment.

Benefit/Cost Analysis :

An economic method for assessing the benefits and costs of achieving alternative health-based standards at given levels of health protection.

Benzene :

A clear, colorless, highly refractive flammable liquid derived from petroleum and used in or to manufacture a wide variety of chemical products, including DDT, insecticides, and motor fuels. Also called benzine.

Big Five Energy Sources :

Coal, oil, natural gas, large-scale hydroelectric and nuclear power.

Bioaccumulants :

Substances that increase in concentration in living organisms as they take in contaminated air, water or food because the substances are very slowly metabolized or excreted.

Bioaerosols :

Airborne microbial contaminants, including viruses, bacteria, fungi, algae, and protozoa.

Bioassay :

Diverse sets of analytical methodologies, which utilize living organisms - applications range from assessment of water pollutants to screening pharmaceuticals.

Biocide :

Product typically used to kill microorganisms.

Biocontaminant :

Contaminants that are either life forms (e.g., bacteria) or are derived from living things (e.g., rodent droppings).

Biodegradable :

Waste material composed primarily of constituent parts that occur naturally, are able to be decomposed by bacteria or fungi, and are absorbed into the ecosystem. Wood, for example, is biodegradable, while plastics are not.

Biodiversity :

A large number and wide range of species of animals, plants, fungi and microorganisms. Ecologically, wide biodiversity is conducive to the development of all species.

Bioengineering :

Creation of new organisms with specific attributes through the insertion of the appropriate genetic material into the original organisms genome.

Biological Contamination :

Contamination of a building environment caused by bacteria, molds and their spores, pollen, viruses, and other biological materials. It is often linked to poorly designed and maintained HVAC systems. People exposed to biologically contaminated environments may display allergic-type responses or physical symptoms such as coughing, muscle aches and respiratory congestion.

Biological Impoverishment :

The loss of variety in the biosphere (even when species have not gone completely extinct).

Biological Oxygen Demand (BOD) :

A measure of the amount of oxygen consumed in the biological processes that break down organic matter in water. BOD is used as an indirect measure of the concentration of biologically degradable material present in organic wastes. It usually reflects the amount of oxygen consumed in five days by biological processes breaking down organic waste. BOD can also be used as an indicator of pollutant level, where the greater the BOD, the greater the degree of pollution. Also referred to as "biochemical oxygen demand."

Biological Productivity :

Nature's capability to reproduce and regenerate, thereby accumulating biomass.

Biomagnifications :

The increasing concentration of a substance as it passes into higher trophic levels of a food web. Many Bioaccumulants are also biomagnified.

Biomass :

Plant matter such as trees, grasses, agricultural crops or other biological material. It can provide a renewable source of electrical power, fuel, or chemical feedstock’s.

Biome :

A large-scale category that includes many communities of a similar nature.

Bioremediation :

The use of bacteria and other small organisms (such as single-celled and multicellular microbes and fungi) to clean up or reduce unwanted concentrations of certain substances:

also known as biotreatment.

Biosphere :

1.The part of the earth and its atmosphere in which living organisms exist or that is capable of supporting life.

2. The ecosystem composed of the earth and the living organisms inhabiting it.

Black Water :

Wastewater from toilets and urinals, which contains pathogens that must be neutralized before the water can be safely reused. After neutralization, black water is typically used for non-potable purposes, such as flushing or irrigation.

Blower Door :

A large fan placed in an exterior doorway to pressurize or depressurize a building to determine its air leakage rate expressed in air changes per hour or cubic feet per minute.

BMS :

See "Building Management System."

Bottom-Up Approach :

The development and encouragement of sustainable uses of biodiversity that provides incentives to save species while also respecting the right of all people to support their families and have a decent quality of life.

BREEAM :

Building Research Establishment Environmental Assessment Method (BREEAM) is a comprehensive tool for analyzing and improving the environmental performance of buildings through design and operations. This methodology has been developed by the U.K.-based Building Research Establishment.

Brownfield :

Abandoned, idled or underused real property where expansion or redevelopment is complicated by real or perceived environmental contamination.

Building Automation System (BAS) :

An integration of digital, electronic, and/or pneumatic controls and devices to provide unattended and automatic operation of buildings systems. Systems may include HVAC, elevators, fire suppression, smoke control, security, lighting, and other subsystems.

Building Control System (BCS) :

A system that controls the comfort and safety of a building's assets and environment.

Building Ecology :

The physical environment and systems found inside the building.

Building Envelope :

The exterior surface of a building's construction - the walls, windows, roof and floor. Also referred to as "building shell."

Building for Environmental and Economic Sustainability (BEES) :

Software program developed by the NIST (National Institute of Standards and Technology). It is aimed at designer’s builders, and product manufacturers. It provides a way to balance the environmental and economic performance of building products. BEES measures the environmental performance of building products by using an environmental lifecycle assessment approach specified in the latest versions of ISO 14000 draft standards. All stages in the life of a product line are analyzed:

raw material acquisition, manufacture, transportation, installation, use, and recycling and waste management. Economic performance is measured using the ASTM standard life cycle cost method, which covers the costs of initial investment, replacement, operation, maintenance and repair, and disposal. Environmental and economic performances are combined into an overall performance measure using the ASTM standard for Multi-Attribute Decision Analysis. The BEES methodology is being refined and expanded under sponsorship of the EPA's Environmentally Preferable Purchasing Program. BEE’s currently addresses categories of product choices and is not specific to a type of product.

Building Life Cycle :

The amortized annual cost of a building, including capital costs, installation costs, operating costs, maintenance costs and disposal costs discounted over the lifetime of the building.

Building Management and Control System (BMCS) :

A BMS and BCS integrated together.

Building Management System (BMS) :

A system for centralizing and optimizing the monitoring, operating, and managing of a building. Services may include heating, cooling, ventilation, lighting, security, and energy management.

Building-related Illness (BRI) :

Diagnosable illness whose cause and symptoms can be directly attributed to a specific pollutant source within a building (i.e., Legionnaire's disease, hypersensitivity, pneumonitis). Also see "Sick Building Syndrome."

Buildings Reborn :

The adaptation of old buildings for uses different from their original purpose.

Built Environment :

Structures created by humans (as opposed to the natural environment).

Buoyancy :

The tendency of warmer air or smoke to rise because cooler air is denser.

By-product :

Material, other than the principal product, generated as a consequence of an industrial process or as a breakdown product in a living system.

California Corner :

An Optimum Value Engineering technique that uses two studs (instead of the usual three or four) to make an exterior corner. The result is better insulation and use of fewer resources, in addition to cost savings. Several variations are possible.

Carbon Dioxide :

Odorless gas commonly sourced by respiration, and has been widely used as a measure of the ventilation adequacy of a space. A principle greenhouse gas. It is the result of the oxidation (including active combustion and respiration) of carbon based substances.

Carbon Footprint :

An estimate of how much carbon dioxide an entity (be it person, family or building) produces and releases into the atmosphere (the EPA has a personal calculator at www.epa.gov/climatechange/emissions/ind_calculator.html). The resulting figure is used to buy carbon offsets (see definition) or engage in ameliorative activities such as planting trees.

Carbon Monoxide :

A colorless, odorless and highly toxic gas commonly created during combustion.

Carbon Monoxide :

A colorless, odorless and highly toxic gas commonly created during combustion.

Carbon Neutral :

Reducing energy use and compensating for the amount of carbon dioxide an entity generates through either obtaining energy from renewable sources or offsetting.

Carbon Offsets :

Credits earned for activities that help balance CO2 emissions, such as planting trees. They can also be bought from a provider who uses the money to plant trees, generate renewable energy or conserve energy.

Carbon Rationing :

Limiting the amount of carbon you introduce into the environment each year. Carbon rationing action groups (crags) help you reduce your carbon footprint.

Carbon Sink :

Carbon dioxide is naturally absorbed by things such as oceans, forests, and peat bogs. These are called carbon sinks.

Carbon Tax :

A charge on fossil fuels (coal, oil, natural gas) based on their carbon content. When burned, the carbon in these fuels becomes carbon dioxide in the atmosphere, a significant greenhouse gas.

Carcinogen :

Any substance capable of causing cancer.

Carpet America Recovery Effort (CARE) :

A carpet industry and government voluntary initiative to prevent carpet from burdening landfills, CARE focuses on developing carpet reclamation and recycling methods.

Carrying Capacity :

1.In recreation management, the amount of use a recreation area can sustain without loss of quality.

2. In wildlife management, the maximum number of animals an area can support during a given period.

Category :

LEED Green Building Rating System component. Each LEED prerequisite and credit falls within one of six categories (five Sustainable Categories and one Innovation and Design Process category).

Cellulose :

A fibrous part of plants used to manufacture paper/textiles.

Cellulose Insulation :

Insulation is made from recycled newspaper with borates to provide fire protection.

Central Plant :

An area or building in which the chillers and boilers for a building or group of buildings are located.

CFM :

See "cubic foot/min"

Certified Sustainably Managed :

Wood determined to have been harvested from a sustainable forest that exhibits the same ecological characteristics as a healthy natural forest. A number of certifying organizations have been established to oversee the harvesting of wood for lumber and provide guidelines for preservation of forests.

Chain :

Wood-based materials used in building construction that are supplied from sources that comply with sustainable, forestry practices, protecting trees, wildlife habitat, streams and soil as determined by the Forest Stewardship Council (FSC).

Chain-of-custody Certification :

A product that has met certain requirements throughout its life, beginning from its extraction and production all the way to its distribution and sale.

Chemical Oxygen Demand (COD) :

A measure of the oxygen required to oxidize all compounds, both organic and inorganic, in water.

Chiller :

An A/C device that cools water (instead of air) for distribution via pipes through a building.

Chemical Oxygen Demand (COD) :

A measure of the oxygen required to oxidize all compounds, both organic and inorganic, in water.

Chlorofluorocarbons (CFCs) :

Stable, artificially created chemical compounds containing carbon, chlorine, fluorine and sometimes hydrogen. Chlorofluorocarbons, used primarily to facilitate cooling in refrigerators and air conditioners, have been found to deplete the stratospheric ozone layer which protects the earth and its inhabitants from excessive ultraviolet radiation.

Chronic :

An exposure which spans long time periods - typically years. In toxicology, a chronic health effect is the result of a long term exposure; e.g., emphysema as a result of smoking.

Chronic Toxicity :

The capacity of a substance to cause long-term poisonous health effects in humans, animals, fish, and other organisms.

CITES :

Convention on International Trade in Endangered Species of Wild Fauna and Flora (U.S. Fish and Wildlife Service) provides lists of endangered species of timber and other natural products.

Clean Air Act :

A federal statute enacted in 1963 that was the first of a series of acts and amendments that exerted increasing federal pressure on air polluters to clean up their emissions.

Clean Air Act 1972 :

Ground breaking legislation administered by the EPA that mandates specific measures to protect the air quality and respiratory health of U.S. inhabitants.

Clean Design :

The systematic incorporation of life cycle environmental considerations into product design.

Clean Energy :

Energy created from renewable sources with low environmental impact.

Clean Water Act :

A federal statute enacted in 1972 that has been successful in improving the water quality of lakes and rivers.

Climate :

The temperature, humidity, precipitation, winds, radiation, and other meteorological conditions characteristic of a locality or region over an extended period of time.

Climate Change :

The term "climate change" is sometimes used to refer to all forms of climatic inconsistency, but because the earth's climate is never static, the term is more properly used to imply a significant change from one climatic condition to another. In some cases, "climate change" has been used synonymously with the term "global warming"; scientists, however, tend to use the term in the wider sense to also include natural changes in climate. Also referred to as "global climate change." Also see "Global Warming."

Climate Control :

An HVAC system.

Closed-loop Process :

Part of an industrial production process; not part of a waste management process. Materials reclaimed and returned in a closed-loop process are neither classified as, defined as, nor operate as, a waste, i.e., any discarded material. Materials in a closed-loop process are treated as commodities in a manner designed to avoid loss or release to the environment (See Electronic Code of Federal Regulations (e-CFR), 40 C.F.R. SS 261.4(a) (8)).

Closed-loop Recycling :

When a used product is recycled into a similar product; a recycling system in which a particular mass of material (possibly after upgrading) is remanufactured into the same product (e.g., glass bottles into glass bottles).

Co-products :

Materials that are intentionally, or incidentally, produced when making another product.

Coefficient of Performance (COP) :

Measurement of the steady-state performance of electrically operated systems, including ground-source heat pumps. It is the ratio of useful-energy output to purchased-energy input. Can also refer to gas-fired systems.

Cogeneration :

The simultaneous production of electrical or mechanical energy (power) and useful thermal energy from the same fuel/ energy source such as oil, coal, gas, biomass or solar.

Combination System :

Heating system that uses the domestic water heater for both water and space heating. Hot water is typically piped to a heat exchanger (coil), where a fan blows air over the coil to produce heated air.

Combustion By-Products :

Gases and small particles (e.g., carbon monoxide, nitrogen dioxide, carbon dioxide, sulphur dioxide, water vapor, particles, and unburned hydro-carbons) caused by the incomplete burning of fuels.

Commissioning :

Process by which the operating systems of a building are tested and adjusted prior to occupancy.

Commodity Electricity :

Physical electricity in the absence of the technological, environmental, social, and economic benefits associated with a specific generation source. These benefits are transferable over geographic distance through a tradable instrument called a renewable energy certificate (REC) and can be re-associated with the physical electricity at the point of use.

Compact Fluorescent Lamp (CFL) :

Small fluorescent lamps used as more efficient alternatives to incandescent lighting. Also called PL, CFL, Twin-Tube, or BIAX lamps.

Comparative Risk Analysis :

An environmental decision-making tool used to systematically measure, compare and rank environmental problems or issue areas. The process typically focuses on the risks a problem poses to human health, the natural environment and quality of life, and results in a list (or lists) of issue areas ranked in terms of relative risk

Competitive Exclusion :

A situation where niche overlap is very great and competition is so intense that one species eliminates another from a particular area.

Compost :

Process whereby organic wastes, including food wastes, paper and yard wastes, decompose naturally, resulting in a product rich in minerals and ideal for gardening and farming as a soil conditioner, mulch, resurfacing material or landfill cover

Composting :

A process whereby organic wastes—food, paper, and yard wastes—decompose naturally, resulting in a product rich in minerals and ideal for gardening and farming as a soil conditioner, mulch, resurfacing material, or landfill cover.

Concentration :

Amount of a material per unit volume; i.e., milligrams per liter.

Condensation :

The change in matter of a substance to a denser phase, such as the deposit of water vapor from air on a cold surface that has a temperature below the dew point.

Condenser :

An HVAC component used to convert a vapor or gas to a liquid.

Condensing Furnace or Boiler :

Refers to high-efficiency systems that extract such a high percentage of the available energy from gas combustion that the water vapor in the burned gas (combustion products) condenses to liquid water before leaving the furnace.

Conditioned Space :

Area within a house that is heated and/ or cooled. Conditioned space is separated from unconditioned space be a thermal envelope.

Conductor :

A material capable of transmitting electricity, heat, or sound.

Conservation :

Preserving and renewing, when possible, human and natural resources. The use, protection and improvement of natural resources according to principles that will ensure their highest economic or social benefits.

Conservation Easements :

A preservation tool that may be used by a land trust or conservation group to limit development.

Constructed Wetland :

A human-made habitat for waterfowl and other life, often using Graywater or rainwater catchment overflow.

Construction Administration (CA) :

The representation of the owner relative to the integrity of the design.

Construction and Demolition (C&D) Debris :

Nonhazardous materials such as asphalt, concrete, brick, lumber, wallboard, roofing materials, ceramics, and plastics resulting from construction, deconstruction, remodeling, repair, cleanup, or demolition operations.

Construction Waste Management Plan (CWMP) :

A plan that diverts construction debris from landfills through the processes of recycling, salvaging and reusing.

Consumption :

The use of goods and services, materials and energy, by humans.

Contaminant :

Any physical, chemical, biological or radiological substance or matter that has an adverse effect on air, water or soil.

Contamination :

Introduction into water, air and soil of microorganisms, chemicals, toxic substances, wastes or wastewater in a concentration that makes the medium unfit for its next intended use. Also applies to surfaces of objects, buildings, and various household and agricultural use products.

Contingent Valuation Method (CVM) :

A method that attempts to "objectively" measure the dollar value of changes in environmental quality; often uses questionnaires and other surveys that ask people what they would pay for various environmental improvements.

Continuous Commissioning :

An on-going program of structured commissioning throughout the lifetime of a building.

Conventional Power :

Power produced from non-renewable fuels such as coal, oil, nuclear and gas, also known as traditional power.

Cooling Load :

The amount of heat generated within a building space (from occupants, electrical equipment, artificial lighting, solar radiation, etc.) that the HVAC system must remove.

Cooling Tower :

A structure outside or on top of a building used to extract heat from water that has been used for cooling.

Coproduct :

A marketable by-product from a process. This includes materials that may be traditionally defined as wastes such as industrial scrap that is subsequently used as a raw material in a different manufacturing process.

Cradle to Cradle :

A certification system and philosophy established by architect William McDonough based on the idea that products and the built environment should be designed in a closed system so that when they are no longer useful, they provide fuel for new products or natural cycles, eliminating waste. This framework seeks to create production techniques that are not just efficient, but essentially waste-free. In cradle-to-cradle production, all material inputs and outputs are seen either as technical or biological nutrients. Technical nutrients can be recycled or reused with no loss of quality and biological nutrients can be composted or consumed.

Cradle-to-Grave :

A term used in life-cycle analysis to describe the entire life of a material or product up to the point of disposal. Also refers to a system that handles a product from creation through disposal.

Credit :

LEED Green Building Rating System component. Compliance is optional and meeting credit criteria results in the earning of points toward certification.

Credit Interpretation Ruling (CIR) :

Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guides or a special conflict exists that requires resolution.

Criteria Pollutants :

A list of air pollutants identified in the 1970 Clean Air Act Amendments deemed to be critical in controlling air pollution and for which National Ambient Air Quality Standards (NAAQS) were established. Criteria pollutants include:

sulfur dioxide (SO2), nitrogen dioxide (NO2), Volatile Organic Compounds (VOCs), particulate matter, carbon monoxide (CO), and lead (Pb).

Cross Ventilation :

The circulation of fresh air through openings on opposite sides of a space.

Cubic ft. /min. (CFM) :

Cubic feet per minute, a common measure of airflow.

Daylighting :

The use of natural light to supplement or replace artificial lighting. Strategies include the proper orientation and placement of windows, use of light wells, light shafts or tubes, skylights, clerestory windows, light shelves, reflective surfaces, and shading, as well as the use of interior glazing to allow light into adjacent spaces.

Daylight Harvesting :

The process of using digital photo sensors to detect daylight levels and automatically adjust the output level of electric lighting to create a balance.

Decay Rate :

Math function that reflects the declining emissions of a product over time.

Deconstruction :

A process to carefully dismantle or remove useable materials from structures, as an alternative to demolition. It maximizes the recovery of valuable building materials for reuse and recycling and minimizes the amount of waste land-filled. Deconstruction options may include:

Reusing the entire building by remodeling, moving the structure to a new location or taking the building apart to reuse lumber, windows, doors, and other materials.

Deep-well Injection :

Deposition of raw or treated, filtered hazardous waste by pumping it into deep wells, where it is contained in the pores of permeable subsurface rock.

Default Power Service :

A safety net service designed to provide energy for short periods of time. However, there is no limit on the length of time you may remain on this service. Default power service will always be available to ensure that consumers receive uninterrupted power when they switch from one energy supplier to another. If for any reason consumers are temporarily without an energy supplier or, in some cases, if they choose not to choose an energy supplier, they will automatically receive default power service.

Deforestation :

The removal of forest cover from an area.

Delisted Species :

Species that are removed from the endangered species list either because it is no longer endangered or threatened, or because it has gone extinct.

Demand-side Waste Management :

Process whereby consumers use purchasing decisions to communicate to product manufacturers that they prefer environmentally sound products packaged with the least amount of waste, made from recycled or recyclable materials, and containing no hazardous substances.

Dematerialization :

The reduction of the size of products, particularly as a way to conserve mineral resources.

Department of Energy (DOE) :

A department of the United States government responsible for energy policy and nuclear safety, including setting industry efficiency standards and monitoring the consumption of energy sources.

Desertification :

The spread of desert-like conditions due to human exploitation and misuse of the land.

Design for Environment :

An engineering perspective in which the environmentally related characteristics of a product, process, or facility design are optimized.

Desuperheater :

Device that takes waste heat extracted by heat pumps or air conditioners and uses it to heat domestic hot water.

Dew Point :

The temperature at which water vapor in air will condense at a given state of humidity and pressure.

Disclosure :

A requirement placed on energy suppliers to provide information to customers on their prices, terms of service, power sources, air emissions and environmental impacts

Disposal :

Final placement or destruction of toxic, radioactive or other wastes; surplus or banned pesticides or other chemicals; polluted soils; and drums containing hazardous materials from removal actions or accidental releases. Disposal may be accomplished through use of approved secure landfills, surface impoundments, land farming, deep-well injection, ocean dumping or incineration.

Distributed Generation :

Small, modular, decentralized, grid-connected or off-grid energy systems located in or near the place where energy is used

Dilution :

The reduction of concentration of airborne contaminants through an increase in fresh air supplied to the space.

Dioxin :

Typically defined as a class of similar chlorinated compounds that are persistent, bioaccumulative, and very toxic. Predominantly related to human activities,manufacturing and incineration.

Distribution :

The process of delivering electricity from the electric distribution system to a consumer’s home or business over local electric lines.

Domestic Hardwood :

Deciduous trees that grow in the United States. This is the only type of wood in the U.S. where on a general scale the growth of new trees easily exceeds the removal rate.

Dose-response :

Relationship between exposure levels and adverse effects.

Downcycling :

A term coined to disparagingly describe creation of a product of lesser intrinsic value manufactured from a material at the end of its service life, which had higher initial end use value; it is important to note that as the term downcycle has historically been used, it does not provide insight into environmental benefit (e.g. there may actually be more environmental benefit from extending the life of a complex polymer prior to energy recovery or taking it apart into its respective building blocks).

Downstream Impacts :

Environmental impacts caused by consumer use and product disposal.

Dust Spot Efficiency :

A measure of a filter's collection efficiency for fine particles.

Dynamic Environmental Chamber :

Well-controlled system (including temperature, relative humidity (RH) and air quality/purity) that utilizes realistic air flows for the assessment of chemical emissions from products and materials

Decay Rate :

Math function that reflects the declining emissions of a product over time.

Dose-response :

Relationship between exposure levels and adverse effects.

Dynamic Environmental Chamber :

Well-controlled system (including temperature, relative humidity (RH) and air quality/purity) that utilizes realistic air flows for the assessment of chemical emissions from products and materials

Earth Sheltered Design :

A home designed to be built partially or completely below ground, either by digging into existing ground or by covering over parts of the house. This design utilizes the constant temperature of the soil to improve energy efficiency and reduces environmental impact.

Earth Summit :

The United Nations Conference on Environment and Development (UNCED), held an international meeting in Rio de Janeiro in June 1992 to discuss environmental and development issues.

Earth's Thermal Energy :

A little below the surface, the earth keeps a constant temperature close to the human comfort level, and this type of heating can be used efficiently for geothermal heating systems.

Eco-Assessment :

An evaluation of your home or workplace with the aim of cutting your energy and water usage.

Ecodesign :

A design process that considers the environmental impacts associated with a product throughout its entire life:

from acquisition of raw materials through production/manufacturing and use to end of life. Ecodesign seeks to improve the aesthetic and functional aspects of the product with due consideration to social and ethical needs while simultaneously reducing environmental impacts.

Eco-friendly :

Having little or no impact on the native ecosystem.

Ecology :

A branch of science concerned with the interrelationship of organisms and their environment.

Ecology, first law of :

Garrett Hardin's concept that "we can never do merely one thing; sometimes referred to as the "Law of Unintended Consequences."

Ecological Impact :

The effect that a human-caused or natural activity has on living organisms and their nonliving environment.

Ecological Indicator :

A characteristic of an ecosystem that is related to or derived from a measure of biotic or a biotic variable that can provide qualitative information on ecological structure and function. An indicator can contribute to a measure of integrity and sustainability.

Ecological/Environmental Sustainability :

Maintenance of ecosystem components and functions for future generations.

Ecological Footprint :

The area of land and water needed to produce the resources to entirely sustain a human population and absorb its waste products with prevailing technology.

Ecosystem :

An interconnected and symbiotic grouping of animals, plants, fungi and micro-organisms that sustains life through biological, geological and chemical activity.

Ecosphere :

The "biobubble" that contains life on earth, in surface waters, and in the air.

Electric Utility :

An entity owning and operating transmission and/or distribution facilities and delivering electric energy to customers

Electricity :

A property of matter that results from the presence or movement of electric charge.

Electrostatic Air Cleaner :

A device that has an electrical charge to trap particles traveling in the airstream.

Embodied Energy :

The total of the energy required to produce a service or product. Included are the product's raw material extraction, transport, manufacturing, assembly, and installation, as well as capital and other costs of a specific material, in addition to disassembly, deconstruction, and/or decomposition.

Emissions :

The release of gases, liquids and/or solids from any process or industry. Liquid emissions are commonly referred to as effluents.

Emission Controls :

Any measure that reduces emissions into air, water or soil. The most effective emission controls involve the redesign of the process so less waste is produced at the source. Common emission controls are wastewater treatment plants, stack scrubbers and in-plant, solid waste reduction programs.

Emission Factor :

Quantity of a substance or substances released from a given area or mass of a material at a set point in time; i.e., milligrams per square meter per hour.

Emission Rate :

A measure of the quantity of a chemical released into the air from a given quantity of a source during a given amount of time.

Emission Standard :

Either a voluntary guideline or a government regulation that specifies the maximum rate at which a contaminant can be released from a source.

Emissions :

The release of gases, liquids and/or solids from any process or industry. Liquid emissions are commonly referred to as effluents.

Emissions Offsets :

An approach to local emissions control by reduction of existing sources to allow for the addition of new sources.

EMS :

See "Energy Management System."

Encapsulation :

The treatment of asbestos-containing material with a liquid that covers the surface with a protective coating or embeds the fibers in an adhesive matrix to prevent their release into the air.

Endangered Species Act of 1973 :

An act that directs the U.S. Fish and Wildlife Service to maintain a list of species that are endangered (in immediate danger of extinction) or threatened (likely to be endangered soon).

Energy :

The capacity for doing work, a force applied through a distance.

Energy & Atmosphere (EA) :

LEED Rating System category. Prerequisites and credits in this category focus on the individual aspects of energy efficiency, lighting, HVAC, and appliances and equipment.

Energy Conservation :

Decreasing the demand for use of energy.

Energy Efficiency :

The ratio of energy output of a conversion process or a system to its energy input.

Energy Efficiency Mortgage (EEM) :

EEM’s recognize that the monthly energy bill savings from improved energy efficiency can more than offset the increased monthly mortgage cost attributed to energy-efficiency upgrades. Some products allow a higher loan-to-income or debt-to-income ratio while other newer, more innovative products finance 100 percent of all cost-effective energy efficiency upgrades in the mortgage, thereby eliminating any increased down payment and requalification requirements.

Energy Efficiency Ratio (EER) :

Instantaneous efficiency of air conditioners measured at standard test conditions. The amount of cooling provided per unit of electricity purchased. The higher the EER, the more efficient the air conditioner.

Energy Factor (EF) :

Overall efficiency of a water heater or other appliance. The amount of hot water produced per unit of gas or electricity purchased. The higher the energy factor number, the more efficient the water heater.

Energy Management System :

A control system capable of monitoring environmental and system loads and adjusting HVAC operations accordingly in order to conserve energy while maintaining comfort.

Energy Modeling :

A computer model used to analyze a building's energy systems in order to project its possible consumption rate.

Energy Plus Building :

A building that over a typical year produces more energy from on-site renewable energy sources than it consumes. See also "Zero Energy Building."

Energy Recovery :

Obtaining usable energy by consuming waste through a variety of processes.

Energy Star Home :

An Energy Star Home Is predicted to use 30 % less energy that houses build to the Model Energy Code (MEC) while maintaining or improving indoor air quality. The ENERGY STAR Home Program of the U.S. Environmental Protection Agency and the U.S. Department of Energy.

Energy Star Rating :

The designation given by the EPA and the U.S. Department of Energy (DOE) to appliances and products that exceed federal energy efficiency standards. This label helps consumers identify products that will save energy and money.

Energy Use :

The total energy consumed by a device or system in the course of its operation.

Enthalpy :

A measure of the total heat content within a given sample of air. It is typically used to determine the amount of fresh outside air that can be added to recirculated air for the lowest heating/cooling cost.

Envelope/ Thermal or Building Envelope :

The protective shell of a building that separates the inside environment from the outside environment; includes both an insulation layer and an air infiltration layer.

Environmental Aspect :

The way a manufacturer's activities or products can relate positively or negatively with the environment.

Environmental Audit :

An assessment of a company's (or person's) compliance with environmental requirements.

Environmental Footprint :

For an industrial setting, this is a company's environmental impact determined by the amount of depletable raw materials and nonrenewable resources it consumes to make its products, and the quantity of wastes and emissions that are generated in the process. Traditionally, for a company to grow, the footprint had to get larger. Today, finding ways to reduce the environmental footprint is a priority for leading companies.

Environmental Impact :

Any change to the environment, whether adverse or beneficial, wholly or partially resulting from human activity, industry or natural disasters.

Environmental Preference :

To revise product specifications, policies, and/or purchasing contract terms to request or give preference to products or services that minimize impacts on the environment throughout the process of manufacture, distribution, use, reuse and recycling, and disposal.

Environmental Protection Agency (EPA) :

Established in 1970 to consolidate the federal government's environmental regulatory activities under the jurisdiction of a single agency, the mission of the EPA is to protect human health and to safeguard the natural environment. The EPA ensures that federal environmental laws are enforced fairly and effectively.

Environmental Restoration :

The act of repairing damage to a site caused by human activity, industry or natural disasters. The ideal environmental restoration, though rarely achieved, is to restore the site as closely as possible to its natural condition before it was disturbed.

Environmental Sustainability :

Long-term maintenance of ecosystem components and functions for future generations.

Environmental Testing Verification (ETV) :

An Environmental Protection Agency program that develops testing protocols and verifies the performance of new technologies

Environmental Tobacco Smoke :

Secondhand tobacco smoke exposure.

Environmental Wisdom :

The ability to sort through facts and information about the environment and make correct decisions and plan long term strategies.

Environmentally Friendly :

A term that refers to the degree to which a product may harm the environment, including the biosphere, soil, water, and air.

Environmentally Preferable Products :

Established by Executive Order 13101. Products that have a lesser or reduced effect on human health and the environment when compared with competing products that serve the same purpose. The product comparison may consider raw materials acquisition, production, manufacturing, packaging, distribution, reuse, operation, maintenance, or disposal.

Environmentally Preferable Purchasing :

Environmentally Preferable Purchasing is a United States federal-wide program (Executive Order 13101) that encourages and assists Executive agencies in the purchasing of Environmentally Preferable Products and services.

EPP :

See "Environmentally Preferable Products."

Erosion :

The process of soil and nutrient loss, which leads to a decline in biological productivity of an area. Can also be used metaphorically to refer to depletion. Estuary:

A bay or inlet, often at the mouth of a river, in which large quantities of freshwater and seawater mix together. These unique habitats are necessary nursery grounds for many marine fishes and shellfishes.

Ethylbenzene :

A component of paint formations, and associated with some carpeting, Ethylbenzene off-gasses in the home, in office furniture products, in office buildings, and in subject's breath. Ethylbenzene is considered a chronic toxin, capable of causing fertility problems and development defects.

Etiological :

Relating to cause, such as of disease or disorder.

ETS :

See "Environmental Tobacco Smoke."

Evaporative Cooling :

The drop in temperature occurring with the removal of latent heat that occurs when water evaporates.

Executive Order 13101 :

An executive order signed in 1998, by then President Clinton, directing federal agencies to purchase Environmentally Preferable products and services.

Exfiltration :

The uncontrolled, unintentional, flow of inside air out of a building, such as through cracks, closures that are not airtight, and the everyday use of windows and doors. See also "Infiltration."

Exhaust Air :

The air extracted from a space and discharged outside.

Exotic Species :

A non-native species that is artificially introduced to an area.

Exposure :

Amount of radiation or pollutant present in a given environment that represents a potential health threat to living organisms.

Extinction :

The complete loss of an entire species.

Exterior Grade Plywood :

Uses phenol formaldehyde (a volatile organic compound) as an adhesive rather than the urea formaldehyde used in interior grade plywood and particleboard.

Extinction Vortex :

Term describing the rapid decline and eventual extinction of a species.

Facilities Management System :

The planning, control, and management of buildings for optimizing the use of real estate, interior environment, energy usage, mechanical infrastructure, communication networks, and maintenance. It considers the "life cycle" of the building (e.g., purchase, construction, operation, relocation, renovation, demolition, or sale). In the HVAC industry, the term is sometimes used in a more limited way that is synonymous with a BAS. See "Building Automation System."

Fair trade :

A movement advocating that farmers and producers should receive equitable compensation for their labors, i.e., what counts as a living wage in the country of their origin. TransFair USA is the only U.S. certifier of fair-trade products, which have to comply with the organization's economic, social and environmental criteria before they can carry the fair-trade label.

Fenestration :

An architectural term for windows and their placement.

Fertilizer :

A substance, often an artificial chemical mixture, which is spread on or through the soil to make it more fertile.

Filtration :

The percolation of water through sand and other settled sediment to remove suspended particles.

First Costs :

The initial costs involved in a building project, typically incurred during the construction and installation stages. Compare with "Life-Cycle Costs."

Five E's :

The five potential values of environmental resources:

esthetic (aesthetic), emotional, economic, environmental services, and ethical.

Flex-Duct :

Flexible ductwork made with an interior liner, a layer of insulation, and an outer covering of plastic.

Flow :

The volume of a substance passing a point per unit time (e.g., gallons per hour).

Fluorocarbon :

A non-flammable liquid or gas used as a propellant; often used in spray cans, they are classified as ozone-depleting substances.

Flush Out :

The operation of mechanical systems for a minimum of two weeks using 100 percent outside air at the end of construction and prior to building occupancy to ensure safe indoor air quality. See also "Bakeout."

Fly Ash :

The ash residue from high temperature combustion processes. Electric motor plants using western coal produce a non-toxic fly ash that because of its very high calcium content can be a substitute for Portland cement (the common bonding material in concrete).

Forest Stewardship Council (FSC) :

A non-profit organization, which administers a forestry certification program to assure that businesses supply trees and wood from a forest managed in an ecologically sustainable manner.

Formaldehyde :

Colorless, pungent smelling, toxic material used as an adhering component of glues used in many wood products. It can cause respiratory problems, cancer, and chemical sensitivity. At concentrations above 0.1 ppm in air, formaldehyde can irritate the eyes and mucous membranes, resulting in watery eyes. Naturally occurring but when added it is referred to as urea formaldehyde.

Fossil Fuels :

Carbon-rich deposits in the Earth, such as petroleum (oil), coal, or natural gas, derived from the remains of ancient plants and animals and used for fuel. These are non-renewable resources with a finite supply. They are pollutive, but are so commonly used due to their traditionally low costs.

Fossil Resources :

Electric generation using natural gas, oil, coal, or petroleum coke or other petroleum-based fuels.

Freegan :

A person who lives an anti-consumerist lifestyle that often involves salvaging discarded (but unspoiled) food from supermarket dumpsters.

Fresh Air :

Outside air drawn into a space or HVAC system.

Frost-Protected Shallow Foundation (FPSF) :

Foundation system in which foam insulation is placed around the perimeter of a foundation to reduce heat loss through the slab and/ or below-grade walls, subsequently raising the frost depth of a building and allowing foundations to be as shallow as 16inches below grade.

Fuel Cell :

A technology that uses an electrochemical process to convert energy into electrical power. Often powered by natural gas, fuel cell power is cleaner than grid-connected power sources. In addition, hot water is produced as a by-product that can be used as a thermal resource.

Fugitive Emissions :

Emissions from valves or leaks in process equipment or material storage areas that are difficult to measure and do not flow through pollution-control devices.

Full Spectrum Lights :

Lights that imitate the natural light spectrum and are therefore considered healthier.

Full-Cost Accounting :

An accounting system in which environmental costs are built directly into the prices of products and services.

Fundamental Building Systems Commissioning :

Verification by an outside source that the fundamental building elements and systems are designed, installed and calibrated to operate as intended.

Fungicide :

Pesticides that are used to control, deter or destroy fungi.

Fungus (Fungi) :

Molds, mildews, yeasts, mushrooms and puffballs; a group of organisms that are lacking in chlorophyll and usually non-mobile, filamentous and multicellular. Some grow in soil; others attach themselves to decaying trees and other plants to obtain nutrients. Some are pathogens; others stabilize sewage and digest composted waste.

Future Costs :

Environmental costs of a product which are not paid now, but rather are passed on to future generations.

Generator :

A power plant producing electricity for a large number of people.

Geothermal :

Energy (heat) originating from deep within the Earth.

Geothermal Heat :

A technology that utilizes the warmth from subsurface water to heat buildings, and it also extracts this heat to put back into the ground for cooling.

Geothermal System :

A heat pump that uses the ground or water as a heat source or sink. Efficiency is improved over air source heat pumps as the temperature of the ground or water is more constant and moderate than that of the air. Geothermal systems typically incorporate some method to contribute heat to the domestic hot water system.

Global Climate Change :

A significant alteration from one climatic condition to another, beyond the usual alterations in various climates throughout the globe, as the result of human activities. "Global warming" refers more specifically to temperature, and global climate change encompasses broader changes, such as shrinking glaciers and polar ice and a rising sea level.

Global Economy :

The emerging international economy characterized by free trade in goods and services, unrestricted capital flows and weakened national powers to control domestic economies.

Global Warming :

A process that raises the air temperature in the lower atmosphere due to heat trapped by greenhouse gases, such as carbon dioxide, methane, nitrous oxide, CFCs and ozone. It can occur as the result of natural influences, but the term is most often applied to the warming predicted to occur as a result of human activities (i.e., emissions of greenhouse gases). See "Global Climate Change."

Gray Water :

Untreated or partially treated waste-water that is used for such purposes as watering lawns or flushing toilets (rather than using cleaner water of drinkable quality).

Green :

A practice that works with nature instead of against it.

Green Accounting :

An informal term referring to management accounting systems that specially delineate the environmental costs of business activities rather than including those costs in overhead accounts.

Green Buildings :

Buildings in which environmental considerations are given to design, construction and operation.

Green Design :

A design, usually architectural, is conforming to environmentally sound principles of building, material and energy use. A green building, for example, might make use of solar panels, skylights and recycled building materials.

Green Development :

A development approach that integrates environmental responsiveness (benefiting the surrounding environment), resource efficiency (using resources in the construction, development, and operations of buildings and/or communities in ways that are not wasteful), and sensitivity to existing culture and community (fostering community in design, construction, and operations).

Green Electricity Provider :

A utility or company that generates, purchases, and/or invests in electricity from renewable sources, such as wind or solar power, and sells it to customers for a small premium over standard electricity costs.

Green Roof :

A garden roof with lightweight medium to support low growing plants. It provides evaporative cooling, converts carbon dioxide to oxygen and reduces stormwater runoff. Green roofs can also include reflective roofs (cool roofs).

Green Label :

The Carpet and Rug Institute's certification program for vacuum cleaners. To qualify for the Green Label, vacuums must go through a stringent testing process that measures three key performance factors:

- Soil Removal - The vacuum must remove a set quantity of soil from carpet in four passes.

- Dust Containment - The vacuum must not release more than 100 micrograms of dust particles per cubic meter of air. This protocol evaluates the total amount of dust particles released by the brush rolls, through the filtration bag and via any air leaks from the system, and is more stringent than the National Ambient Air Quality Standards.

- Carpet Appearance Retention - The vacuum should not affect the appearance of the carpet more than a one-step change based on one year of normal vacuum use.

High performance vacuum cleaners have a significant impact on improved indoor air quality (IAQ). At the same time, vacuums that effectively remove and contain soil while keeping the carpet looking good will help carpets last longer. Ultimately, better performing vacuums provide a greater return on investment and ensure a healthier indoor environment.

Green Seal :

A widely recognized green product certification. The Green Seal organization is "an independent, non-profit organization that strives to achieve a healthier and cleaner environment by identifying and promoting products and services that cause a less toxic pollution and waste, conserve resources and habitats, and minimize global warming and ozone depletion. Green Seal has no financial interest in the products that it certifies or recommends in any manufacturer or company."

Green Seal Certified Products :

The Green Seal is awarded to products that have less impact on the environment and work well. To earn the Green Seal a product must meet the Green Seal environmental standard for the category as demonstrated by rigorous evaluation, testing and a plant visit.

Green Seal Recommended Products :

Green Seal publishes reports of product recommendations to provide guidance for institutional purchasers. The recommendations are based on a careful environmental screening of available information on products currently on the market. The recommended products appear to meet the prerequisites for being environmentally responsible based on data provided by their manufacturers. Recommended products have not gone through Green Seal's formal certification process.

Green Technologies :

Environmentally friendly technologies including technologies that promote sustainability via efficiency improvements, reuse/recycling, and substitution.

Greenbelt Zones :

Zones or areas in or around a city where the removal of native vegetation is prohibited and/or parks and other open, undeveloped, and vegated space are protected.

Greenfield :

Semirural real property that is undeveloped, except for possible agricultural use, which is being considered as a site for development

Greenfield Site :

Land on which no urban development has previously taken place; usually understood to be on the periphery of an existing built-up area.

GreenGuard :

Established performance-based standards to define goods such as building materials, interior furnishings, furniture, cleaning and maintenance products, electronic equipment and personal care products with low chemical and particle emissions for use indoor. The GreenGuard standards establish certification procedures including test methods, allowable emissions levels, product sample collection and handling, testing type and frequency, and program application processes and acceptance.

Greenhouse Effect :

1. The warming of earth's surface and lower atmosphere as a result of carbon dioxide and water vapor in the atmosphere, which absorb and reradiate infrared radiation.

2. An intensification of this warming effect brought about by increased levels of carbon dioxide in the atmosphere, resulting from the burning of fossil fuels.

Greenmail :

When companies threaten to close or relocate (often to another country) if they are forced to comply with environmental laws.

Greenwash :

Disinformation disseminated by an organization so as to present an environmentally responsible public image.

Greywater :

Wastewater that doesn't contain contaminates and can then be reused for irrigation after filtration.

Grid :

A term used to describe the network of wires and cables which transport electricity from a power plant.

Groundwater :

A general term for the water beneath the Earth's surface.

Gas Chromatography :

Analytical process by which chemical mixtures are separated into individual components for quantitative and perhaps qualitative analysis.

Geothermal Energy :

Heat that comes from the Earth's interior.

Global Warming :

An increase in the global mean temperature of the Earth that is a result of increased emissions of greenhouse gases that are trapped within the Earth's atmosphere. Global warming is believed to have adverse consequences, such as climate change and a rise in sea levels. The scientific community is in general agreement that the Earth's surface has warmed by about 1°F over the past 140 years.

Green Building :

A building that minimizes its impact on the environment through conservation of energy, water, and other resources, while contributing to the health of its occupants without compromising the aesthetic design.

Green Design :

A design, usually architectural, conforming to environmentally sound principles of building, material and energy use. A green building, for example, might make use of solar panels, skylights and recycled building materials.

Greenhouse Gases :

Any gas that absorbs infrared radiation in the Earth's atmosphere. Carbon dioxide, methane, and nitrogen oxides are of particular concern due to their length of time they remain resident in the atmosphere. Primarily, the emissions of coal-fired power plants and combustion engine automobiles produce carbon dioxide that prevents excess heat from escaping through the atmosphere, thereby raising the surface temperature of the earth. More than 80 percent of all U.S. greenhouse gases are carbon dioxide emissions from energy-related sources.

Green Power :

Electricity generated from renewable energy sources. This includes solar, wind, biomass, geothermal, and hydroelectric power.

Greenwash :

Disinformation disseminated by an organization so as to present an environmentally responsible public image.

Habitat :

1. the natural home of an animal or plant.

2. The sum of the environmental conditions that determine the existence of a community in a specific place.

Habitat Fragmentation :

Habitat disruption where natural habitat is broken into small, relatively isolated sections.

Halocarbons :

Manmade chemicals that, when released into the atmosphere as greenhouse gases, can disrupt global climate patterns. Their most common use is in refrigeration and air conditioning technologies.

Halogen :

A type of incandescent lamp with a higher energy-efficiency than standard ones.

Halons :

Effective fire suppressants, which leave no residue and are of relatively low toxicity. Historically, they have been used in applications where conventional extinguishing agents (e.g., water) would be dangerous or result in significant peripheral damage - (e.g., electronics, electrical, and HVAC.) Note Halons adversely affect stratospheric ozone and are being phased out.

Harvested Rainwater :

Rainwater captured and used for indoor needs, irrigation, or both.

Hazard :

A material or condition that may cause damage, injury, or other harm, frequently established through standardized assays performed on biological systems or organisms. The confluence of hazard and exposure create a risk.

Hazardous Waste :

Wastes that are particularly dangerous or destructive; specifically characterized by one or more of the following properties:

ignitable, corrosive, reactive, or toxic.

Heat Island Effect :

The increase in ambient temperature that occurs over large paved areas compared to natural landscape. See also "Urban Heat Island."

Heat Pump :

Similar to an air conditioner but can operate in reverse to heat as well as cool. Transfers heat (usually from the air) from one location to another.

Heat Recovery or Energy Recovery Ventilator (HRV/ERV) :

A system that reclaims the heat from warm exhaust air exiting a building and uses it to pre-heat entering fresh air.

Heating Seasonal Performance Factor (HSPF) :

Efficiency of a heat pump in the heating mode, taking cycling into account; the amount of heating provided per unit of electricity purchased. The higher the HSPF number, the more efficient the heat pumps.

Heating Ventilation and Air Conditioning (HVAC) :

A term generally used to describe a building's comfort system. In older buildings, heating (radiators), ventilation (windows), and air conditioning (window units) may be separate, but usually these services are integrated into a single system that conditions air that is distributed through ducts.

Heavy Metals :

Elements such as lead, mercury, zinc, copper, cadmium, and so forth, that may be required in trace amounts by organisms, but can cause damage when ingested in larger quantities.

Herbicide :

A chemical substance used to kill plants.

High Efficiency Particulate Air Filter (HEPA) :

An air filter that captures a high percent of all particles, including very small particles not captured by other types of filters.

High Intensity Discharge :

A generic term for mercury, vapor, metal halide, and high pressure sodium lamps and fixtures.

High Performance Building :

A green or sustainable building often with an emphasis on the use of advanced technology, or "smart infrastructure," and its impact on tenant ability to control key building comfort measures such as temperature and light levels to increase performance.

High-quality Duct System :

An alternative system in which all the ducts are sealed with fib rated latex material and fiberglass tape, and then run outside to avoid significant heating and cooling losses and potential health threats caused by de/pressurizing a house.

Historic Image Restoration :

The renovation of a building or community that saves and restores the historic image of that place.

Holistic :

A wide-reaching approach to a theory, a task, or a problem that encompasses all the elements of the system because of the interdependency of those elements.

Home Energy Rating System (HERS) :

A collection of programs throughout the country that assign energy ratings based on predicted energy use of the house. Ratings are either on a scale of 1 to 100 points or 1 to 5-plus stars. Most houses built today without any special attention to energy efficiency typically earn an 80-point or three-star rating.

Horizontal Recycling :

A recycling system that turns a majority of the original product back into a similar product as the original.

Hot Spot :

An area of exceptionally high species richness, especially concentrations of localized rare species that occur nowhere else.

Hydrocarbons (HC) :

Chemical compounds that consist entirely of carbon and hydrogen.

Hydrochlorofluorocarbon (HCFC) :

A fluorocarbon that is replacing chlorofluorocarbon as a refrigerant and propellant in aerosol cans; considered to be somewhat less destructive to the atmosphere.

Hydroelectric Power :

The use of artificial or natural waterfalls to generate electricity.

Hydrological Cycle :

The natural cycle of water from evaporation, transportation in the atmosphere, condensation (rain), and the flow back to the ocean.

Hydronic Heating :

A radiant heat system that distributes hot water through pipes, either to radiators or through a thermal mass floor. The floor absorbs heat and evenly radiates it to the living space.

Hydrophilic :

Having a strong affinity for water; attracting, dissolving in or absorbing water.

Hydrophobic :

Having a strong aversion to water; repelling water.

Hydropower (hydroelectricity) :

Clean energy technology that uses moving water to produce electricity. Water flows through a hydraulic turbine, which spins and then rotates generators and converts rotational energy into electricity.

Hypersensitivity :

Exaggerated immune system response to an allergen.

Habitat :

1.The natural home of an animal or plant.

2. The sum of the environmental conditions that determine the existence of a community in a specific place.

Harvested Rainwater :

The rain that falls on a roof and is channeled by gutters to a storage tank or cistern.

Heat Island Effect :

A phenomenon that occurs in developed areas where the replacement of natural land cover with paving, buildings, roads, parking lots, and other structures result in an increase in outdoor temperatures. The heat island effect can be mitigated by vegetation, green roofs, and light colored materials that reflect heat. Urban heat islands can be as much as 10°F hotter than the surrounding undeveloped areas.

Heat Recovery Systems :

Building mechanical systems that capture waste heat from another system and use it to replace heat that would otherwise come from a primary energy source.

Hydrocarbons (HC) :

Chemical compounds that consist entirely of carbon and hydrogen.

Hydrophilic :

Having a strong affinity for water; attracting, dissolving in or absorbing water.

Hydrophobic :

Having a strong aversion to water; repelling water.

Hypersensitivity :

Exaggerated immune system response to an allergen.

IESNA (Illumination Engineering Society of North America) :

The professional society of lighting engineers, including those from manufacturing companies and other professionally involved in lighting. It produces standard practice documents for applying proper lighting techniques to indoor and outdoor spaces.

Impact Analysis :

The second stage of life cycle assessment, in which the environmental impacts of a process, product, or facility are determined.

Improvement Analysis :

The third stage of life cycle assessment, in which design for environment techniques are used in combination with the results of the first and second LCA stages to improve the environmental plan of a process, product, or facility.

Incineration :

The burning of trash and garbage at high temperatures in a large furnace.

Indicator Species :

A species in a community or ecosystem that is more susceptible to disturbances than most other species.

Indicators :

(1) A measurement or reporting tool used to gauge how well a society is achieving its economic, environmental and societal goals. (2) A species of plant or animal, or a community, whose occurrence serves as evidence that certain environmental conditions exist.

Indigenous Materials :

Building with materials that are produced in an area near to where the construction is taking place. This reduces building costs and helps to boost local economies.

Indoor Air Pollution :

Chemical, physical, or biological contaminants in indoor air.

Indoor Air Quality (IAQ) :

ASHRAE defines acceptable indoor air quality as air in which there are no known contaminants at harmful concentrations as determined by cognizant authorities and with which 80% or more people exposed do not express dissatisfaction

Indoor Environmental Quality (IEQ) :

LEED Rating System category. Prerequisites and credits in this category focus on the strategies and systems that result in a healthy indoor environment for building occupants.

Innovation & Design Process (ID) :

LEED Rating System category. Prerequisites and credits in this category recognize projects for innovative building features and sustainable building knowledge.

Insulating Concrete Form (ICF) :

Concrete form-wall constructed of foam insulation that remains in place after the concrete cures.

Integrated Coastal Zone Management :

A continuous and dynamic process by which decisions are made for the sustainable use, development and protection of coastal and marine areas and resources. ICM acknowledges the interrelationships that exist among coastal and ocean uses and the environments they potentially affect.

Integrated Design Team :

The team of all individuals involved in a project from very early in the design process, including the design professionals, the owner's representatives and the general contractor and subcontractors.

Integrated Pest Management :

A cost-effective way to prevent pests by using less invasive techniques to both animal and occupant alike.

Integrated Waste Management :

The complementary use of a variety of practices to handle solid waste safely and effectively. Techniques include source reduction, recycling, composting, combustion and landfilling.

Intent :

LEED Green Building Rating System component. Identifies the primary goal of each prerequisite or credit.

Inventory Analysis :

The first stage of life cycle assessment, in which the inputs and outputs of materials and energy are determined for a process, product, or facility.

Irreversible Disassembly :

Disassembly in which brute force is used to recover the bulk of the principal materials from a product, and in which no refurbishment and reuse of components or modules is possible.

Indigenous Materials :

Building materials that are mined, manufactured, or fabricated locally to reduce transportation cost and increase the viability of the local economy.

Indoor Air Quality (IAQ) :

The content of interior air that could affect the health and comfort of building occupants. Good air quality inside a building results from streaming an appropriate amount of outside air into the building and regulating proper filtration, air distribution, and removal of indoor pollutants through he use of proper ventilation.

Intelligent Materials :

Materials able to adapt to their environment by altering their properties, such as thermo chromic glazing that changes its transparency in response to changing temperatures.

Integrated Waste Management :

The complementary use of a variety of practices to handle solid waste safely and effectively. Techniques include source reduction, recycling, composting, combustion and landfilling.

Keystone Species :

A certain species that one or more other species are dependent upon for food, reproduction, or some other basic need.

Kyoto Protocol :

In December 1997, a delegation from 160 countries came together on climate change and adopted an agreement, under which the industrialized nations agreed to reduce their greenhouse gas emissions by an average of 5.2 percent below 1990 emissions levels by 2010.

Land Trust Alliance :

An association of hundreds of local land trusts, dedicated to preserving open space and natural habitat, in the United States.

Landfills :

1. Sanitary landfills are disposal sites for non-hazardous solid wastes spread in layers, compacted to the smallest practical volume and covered by material applied at the end of each operating day. 2. Secure chemical landfills are disposal sites for hazardous waste, selected and designed to minimize the chance of release of hazardous substances into the environment.

Leachate :

The solution that is produced by the action of percolating water through a permeable solid, as in a landfill.

Lead :

A toxic pollutant, typically found in older homes, that is a component of lead-based paint.

LEED (Leadership in Energy and Environmental Design) :

A voluntary, consensus-based national rating system for developing high-performance, sustainable buildings. Developed by the USGBC, LEED addresses all building types and emphasizes state-of-the-art strategies for sustainable site development, water savings, energy efficiency, materials and resources selection, and indoor environmental quality. LEED is a practical rating tool for green building design and construction that provides immediate, measurable results for building owners and occupants.

LEED Steering Committee (LEED SC) :

Oversight committee of the USGBC responsible for direction and decisions for the LEED program.

LEED Technical and Scientific Advisory Committee (LEED TSAC) :

The Technical and Scientific Advisory Committee is a standing LEED committee comprised of six to eight individuals representing a diversity of building community perspectives and technical areas of competency. The Technical and Scientific Advisory Committee provides support for each of the LEED products and advice on topics as assigned by the LEED Steering Committee and the USGBC Board of Directors.

LEED-CI :

LEED for Commercial Interiors. One of the six LEED Rating Systems. LEED for Commercial Interiors focuses on tenant improvements in interior spaces in single and multi-tenant buildings.

LEED-CI Reference Guide :

The LEED-CI Reference Guide is a supporting document to the LEED-CI Green Building Rating System. The Guide is intended to assist project teams understand LEED-CI criteria and the benefits of compliance with the criteria.

LEED-CS :

LEED for Core and Shell. One of the six LEED Rating Systems. LEED for Core and Shell focuses on buildings being developed where the developer is responsible for the core and shell of the structure and has no responsibility for the design and decisions concerning the interior space fit-outs.

LEED-EB :

LEED for Existing Buildings. One of the six LEED Green Building Rating Systems. LEED for Existing Buildings establishes a set of performance standards for the sustainable upgrades and operation of existing buildings.

LEED-H :

LEED for Homes. One of the six LEED Green Building Rating Systems. LEED for Homes is under development and will address single-family homes, both detached and attached, and multifamily residential buildings with up to three stories, developed on a single lot.

LEED-NC :

LEED for New Construction. One of the six LEED Green Building Rating Systems. LEED for New Construction focuses on the design and construction process for new construction and major reconstruction of buildings.

LEED-NC Reference Guide :

The LEED-NC Reference Guide is a supporting document to the LEED-NC Green Building Rating System. The Guide is intended to assist project teams understand LEED-NC criteria and the benefits of compliance with the criteria.

LEED-ND :

LEED for Neighborhood Developments. One of the six LEED Green Building Rating Systems. LEED for Neighborhood Developments is under development and will address the design and location of new, multi-lot residential, commercial, or mixed-use developments.

LEED™ Rating System :

LEED (Leadership in Energy and Environmental Design) is a self assessing system designed for rating new and existing commercial, institutional, and high-rise residential buildings. It evaluates environmental performance from a "whole building" perspective over a building's life cycle, providing a definitive standard for what constitutes a green building.

LEED® Green Building Rating System :

The LEED (Leadership in Energy and Environmental Design) Green Building Rating System is a voluntary, consensus based, market driven building rating system based on existing proven technology. The LEED Green Building Rating System represents the USGBC's effort to provide a national standard for what constitutes a "green building." Through it's use as a design guideline and third-party certification tool, the LEED Green Building Rating System aims to improve occupant well-being, environmental performance and economic returns of building using established and innovative practices, standards, and technologies.

Life Cycle Analysis (LCA) :

The assessment of a product's full environmental costs, from raw material to final disposal, in terms of consumption of resources, energy and waste.

Life Cycle Assessment :

The comprehensive examination of a product's environmental and economic effects throughout its lifetime, including raw material extraction, transportation, manufacturing, use and disposal.

Life Cycle Cost (LCC) Method :

A technique of economic evaluation that sums over a given study period the costs of initial investment (less resale value), replacements, operations (including energy use), and maintenance and repair of an investment decision (expressed in present or annual value terms).

Life Cycle Inventory (LCI) :

An accounting of the energy and waste associated with the creation of a new product through use and disposal.

Life Cycle of a Product :

All stages of a product's development, from extraction of fuel for power to production, marketing, use and disposal.

Life-Support Systems :

According to the World Conservation Union (IUCN), the biophysical processes "that sustain the productivity, adaptability and capacity for renewal of lands, waters, and/or the biosphere as a whole."

Light Pollution :

Excess "waste" light given off by outside sources (or sources visible from the outside) at night.

Light Shelf :

A daylighting strategy that allows natural light to bounce off a shelf located in a window and onto the building to bring light deep into a space.

Light-Emitting Diode :

A long-lasting illumination technology used for exit signs which requires very little power.

Limiting Nutrient :

The nutrient in shortest supply in a particular ecosystem.

Low Biocide :

Paint that does not contain toxic additives, such as fungicide or pesticide.

Low Emissivity Windows :

Windows with special coatings that transmit most of the sun's light but block heat radiation from passing through.

Low-Emittance (Low-E) Windows :

Windows with a thin, invisible, metallic coating on one or more glazing surfaces that reduces the radiation of heat from windows. Low-e glass has a thin, invisible coating that reduces the flow of radiant heat through windows. The most common coating reduces solar heat gain and increases resistance to radiant heat loss through windows.

Low-flow Toilet :

A toilet that uses less water than a traditional unit, therefore lowering costs by using water more efficiently.

Low-pressure Drop Air Filers :

High-efficiency air filters with an extended surface, which allows for more filtration without an increase in horsepower.

Lowest Observed Adverse Effect Level (LOAEL) :

The lowest level of a stressor that causes statistically and biologically significant differences in test samples as compared to other samples subjected to no stressor.

Life Cycle Analysis (LCA) :

The assessment of a product's full environmental costs, from raw material to final disposal, in terms of consumption of resources, energy and waste.

Life Cycle Inventory (LCI) :

An accounting of the energy and waste associated with the creation of a new product through use and disposal.

Low-E (Low-Emissive) :

Glass that reflect heat, not light, and therefore keeps spaces warmer in winter and cooler in summer.

Lowest Observed Adverse Effect Level (LOAEL) :

The lowest level of a stressor that causes statistically and biologically significant differences in test samples as compared to other samples subjected to no stressor.

Manual-J :

Method developed by the air conditioning Contractors of America to size heating and cooling equipment.

Mass Effect :

Describes the effect of a high-mass material on heating or cooling requirements. High mass materials such as concrete, used in floors and walls, can absorb and store significant amounts of heat, which is later released. In some climates (those with lots of sunshine, low humidity, and large daily temperature fluctuations), high-mass materials can mean a reduction in cooling and heating requirements by delaying the time at which the heat is released into the house.

Mass Spectrum :

Characteristic fingerprint of a substance, which makes its identification possible.

Mastic :

Strong, flexible material, which has a thick, creamy consistency when applied, used to seal ductwork. Also used to describe a type of ceramic adhesive.

Material Safety Data Sheets (MSDS) :

A compilation of information required under the OSHA Commercial Standard on the identity of hazardous chemicals, health, and physical hazards, exposure limits and precautions.

Materials Recovery Facility :

Commonly called a MRF (pronounced "murf"). A processing facility that removes recyclables from the waste stream. A "dirty MRF" removes reusable materials from unseparated trash; a "clean MRF" separates commingled recyclables.

Mechanical Ventilation :

The use of fans and intake and exhaust vents to mechanically distribute ventilation and other conditioned air. See also "Ventilation, Natural."

Megalopolis :

A single vast urban area formed by the expansion and merging of adjacent cities and their suburbs.

Methane :

A colorless, nonpoisonous, flammable gas created by anaerobic decomposition of organic compounds. A major component of natural gas used in the home.

Microbial Growth :

The amplification or multiplication of microorganisms such as bacteria, algae, diatoms, plankton and fungi.

Microbiological Organism :

Broad range of living organisms, which typically can be viewed only through a microscope.

Micron :

A measure of length; one millionth of a meter.

Model Energy Code (MEC) :

A building code that requires houses to meet certain energy efficiency-related minimums such as insulation levels or energy consumption. Like most building codes, it is adopted on either a state or local basis, if at all, and may be amended.

Mold :

Mold is a fungus that typically grows in a filamentous cobweb-like mass under damp conditions and is capable of producing staggering numbers of reproductive spores in as little as a few days. Molds are non-chlorophyll containing entities, which require organic matter, living or dead, for survival. Mold is a critical participant in the "recycling" of dead organic material on the planet. Molds are extraordinarily diverse in character and their relationship with humans span the positive (e.g., food, antibiotics) to the negative (e.g., pathogens, antigens, toxins).

Montreal Protocol :

An agreement reached in 1987 at a meeting in Montreal, Canada, whereby a number of industrialized countries pledged to freeze CFC production at 1986 levels and then gradually decrease CFC production to 50% of 1986 levels by 1999.

Multiple-Use Development :

The use of a piece of land for different purposes simultaneously, such as the use of riverside land for water filtration by plants, recreation, flood buffers, and wildlife habitat.

Mutagen :

Any agent, such as a chemical, ultraviolet light, or a radioactive element, that can cause or accelerate the rate of mutation within an organism.

Methane :

A colorless, nonpoisonous, flammable gas created by anaerobic decomposition of organic compounds. A major component of natural gas used in the home.

Microbial Growth :

The amplification or multiplication of microorganisms such as bacteria, algae, diatoms, plankton and fungi.

Microbiological Organism :

Broad range of living organisms, which typically can be viewed only through a microscope.

Microclimate :

Localized climate conditions within an urban area or building.

Micron :

A measure of length; one millionth of a meter.

National Ambient Air Quality Standards (NAAQS) :

Standards established by the EPA that apply to outdoor air throughout the country.

National Institute of Occupational Safety and Health (NIOSH) :

agency of the Centers for Disease Control of the Department of Health and Human Services. NIOSH is the research arm of OSHA.

Natural site criteria :

approach where the locations of roads, buildings, and other structures are selected to be where the geological and biological factors are most favorable; essentially "working with nature" when selecting locations for human-made structures.

Natural Ventilation :

e process of air moving into and out of a building through intentional routes (e.g., windows, grilles), without the assistance of mechanical equipment.

Net Present Value :

termination of current value of buildings and components in today's dollars that reflects a stream of current and future benefits and costs; projected future costs and benefits must be discounted to give a fair value in today's dollars.

Neurotoxin :

substance that can cause damage to nerve cells or the nervous system.

Niche :

organisms "occupation," or how it lives.

Nitric Oxide (NO) :

as formed by combustion under high temperature and high pressure in an internal combustion engine, and then converted by sunlight and photochemical processes in ambient air to nitrogen oxide. Nitric oxide is a precursor of ground level ozone pollution, or smog.

Nitrogen Oxide (NOx) :

The result of photochemical reactions of nitric oxide in ambient air. It is a major component of photochemical smog, a product of combustion from transportation and stationary sources, and a major contributor to the formation of ozone in the lower atmosphere and to acid deposition.

No Observable Adverse Effect Level (NOAEL) :

An exposure levels at which there are no statistically or biologically significant increases in the frequency or severity of adverse effects between the exposed population and its appropriate control; some effects may be produced at this level, but they are not considered as adverse, or as precursors to adverse effects. In an experiment with several NOAELs, the regulatory focus is primarily on the highest one, leading to the common usage of the term NOAEL as the highest exposure without adverse effects.

Non-Potable Water :

Undrinkable water.

Nonhazardous Waste :

Waste that is not classified as hazardous.

National Ambient Air Quality Standards (NAAQS) :

Standards established by the EPA that apply to outdoor air throughout the country.

Nitric Oxide (NO) :

A gas formed by combustion under high temperature and high pressure in an internal combustion engine, and then converted by sunlight and photochemical processes in ambient air to nitrogen oxide. Nitric oxide is a precursor of ground-level ozone pollution, or smog.

Nitrogen Oxide (NOX) :

The result of photochemical reactions of nitric oxide in ambient air. It is a major component of photochemical smog, a product of combustion from transportation and stationary sources, and a major contributor to the formation of ozone in the lower atmosphere and to acid deposition.

Nonrenewable Energy :

Energy derived from depletable fuels (oil, gas, coal) created through lengthy geological processes and existing in limited quantities on the earth.

Non-Renewable Energy Resources :

Energy resources that cannot be restored or replenished by natural processes and therefore are depleted through use. Commonly used non-renewable energy resources include coal, oil, natural gas, and uranium.

Nonrenewable Resource- :

A resource that cannot be replaced in the environment (i.e., fossil fuels) because it forms at a rate far slower than its consumption.

Nuclear Power :

The use of nuclear fission reactions to generate electricity.

Occupational Safety and Health Administration (OSHA) :

Occupational Safety and Health Administration, a branch of the U.S. Department of Labor responsible for establishing and enforcing safety and health standards in the workplace.

Occupied Zone :

The volume of a conditioned space containing the occupants of the space, typically considered extending from floor level up to a height of 6 feet (1.8m).

Ocean Energy :

Waves, tides, differential heat layers, and other sources of energy directly related to the world's oceans.

Off-Gassing :

The emission of volatile organic compounds from synthetic and natural products. These fumes are unpleasant to breathe and may be hazardous to occupant health. Many new paints, carpeting, sealants, adhesives, and other building materials will do this for a time after installation.

Off the Grid :

A system that runs on renewable energy sources independent of a conventional public utility grid.

Odor Threshold :

The minimum odor of a water or air sample that can just be detected after successive dilutions with odorless water.

Open-loop Process :

Any process that does not fit the definition of "closed-loop process."

Open-loop Recycling :

A recycling system in which a product made from one type of material is recycled into a different type of product (e.g., used newspapers into toilet paper). The product receiving recycled material itself may or may not be recycled.

Optimum Value Engineering (OVE) :

Sometimes referred to as Advanced Framing. OVE Framing techniques use less lumber and therefore improve a structureâ €™s level of insulation. Techniques include 24-inch on-center stud layout, single top plates, engineered header sizes, and special corner and wall configurations.

Organic Compound :

Vast array of substances typically characterized as principally carbon and hydrogen, but that may also contain oxygen, nitrogen and a variety of other elements as structural building blocks.

Organic Farming :

Avoiding the use of synthetic chemicals as fertilizers, pesticides, and herbicides when farming.

OSHA :

Occupational Safety and Health Administration.

Overshoot :

The growth beyond an area's carrying capacity, which leads to a "crash." Ozone (O3) A naturally occurring, highly reactive, irritating gas comprising triatomic oxygen formed by recombination of oxygen in the presence of ultraviolet radiation. This gas builds up in the lower atmosphere as smog pollution, while in the upper atmosphere it forms a protective layer that shields the earth and its inhabitants from excessive exposure to damaging ultraviolet radiation.

Ozone Depletion :

Destruction of the earth's ozone layer, which can be caused by the photolytic breakdown of certain chlorine- and/or bromine-containing compounds (e.g., chlorofluorocarbons), which catalytically decompose ozone molecules.

Ozone Hole :

A thinning break in the ozone layer. Designation of amount of such depletion as an "ozone hole" is made when the detected amount of depletion exceeds 50 percent. Seasonal ozone holes have been observed over the Antarctic and arctic regions, part of Canada, and the extreme northeastern United States.

Ozone Layer :

The protective layer in the atmosphere, about 12-15 miles above sea level that absorbs some of the sun’s ultraviolet rays thereby reducing the amount of potentially harmful radiation that reaches the earth's surface.

Ozone (O3 ) :

A naturally occurring, highly reactive, irritating gas comprising triatomic oxygen formed by recombination of oxygen in the presence of ultraviolet radiation. This gas builds up in the lower atmosphere as smog pollution, while in the upper atmosphere it forms a protective layer that shields the earth and its inhabitants from excessive exposure to damaging ultraviolet radiation.

Ozone :

A form of oxygen found naturally that provides a protective layer shielding the Earth from ultraviolet radiation's harmful effects on humans and the environment. Ground level ozone is the primary component of smog, produced near the Earth's surface through complex chemical reactions of nitrogen oxides, volatile organic compounds, and sunlight.

Particulate Matter :

Solid material that escapes from combustion processes and can be inhaled, causing potential health problems.

Particulate Pollution :

Pollution made up of small liquid or solid particles suspended in the atmosphere or water supply.

Passive Design :

Building design and placement in home construction that permits the use of natural thermal processes—convection, absorption, radiation, and conduction—to support comfort levels.

Passive Cooling :

A system whereby a building's structure (or an element of it) permits increased ventilation and retention of coolness within the building components. The intention is to minimize or eliminate the need for mechanical means of cooling.

Passive Heating :

A system whereby a building's structure (or an element of it) is designed to allow natural thermal energy flows, such as radiation, conduction, and natural convection generated by the sun, to provide heat. The home relies solely or primarily on non-mechanical means of heating.

Passive Solar Design :

A type of architecture that uses the inherent characteristics of a building to capture heat and light from the Sun.

Passive Solar Heating :

Using the sun's energy (in the form of heat) to diminish a building's heating load, usually through the use of large window areas that permit light penetration upon some massive material to use the material's thermal storage capacity.

Passive Ventilation :

The use of convective airflows that result from the tendency of warm air to rise and cool air to sink, while also taking advantage of prevailing winds. Many passive ventilation systems rely on building occupants to control window and vents as indicated by conditions inside and outside the building.

Pathogens :

Microorganisms (i.e., bacteria, viruses or parasites) that can cause disease in humans, animals and plants.

Performance Period :

Period during which performance data is collected for an application for LEED certification.

Permaculture Design :

A system of assembling conceptual, material and strategic components in a pattern that functions to benefit life in all forms.

Permeable :

Open to passage of fluids or gases.

Pervious Paving :

Material that allows water to penetrate to the soil below, thereby decreasing the amount of water needed by the water system.

Pesticide :

Any chemical used for killing insects, weeds, etc.

Petroleum :

Crude oil or any fraction thereof that is liquid under normal conditions of temperature and pressure. The term includes petroleum-based substances comprising a complex blend of hydrocarbons derived from crude oil through the process of separation, conversion, upgrading and finishing, such as motor fuel, jet oil, lubricants, petroleum solvents and used oil. pH Scale A logarithmic scale that is used to measure acidity; 1 is very acidic, 7 is neutral, and 14 is very basic (alkaline).

Photosynthesis :

The biological process in chlorophyll-containing cells that transforms sunlight, water, and carbon dioxide into plant matter (or biomass).

Photochemical Oxidants :

Air pollutants formed by the action of sunlight on oxides of nitrogen and hydrocarbons.

Photochemical Smog :

Air pollution caused by chemical reactions of various pollutants emitted in the presence of sunlight.

Photovoltaics (PV) :

The use of semiconductor technology to generate electricity directly from sunlight.

Photovoltaic Cells :

Devices that use semiconductors to convert sunlight directly into electricity.

Points :

Compliance with each LEED credit earns one or more points toward certification. Compliance with prerequisites is required and does not earn points.

Pollutant :

Generally, any substance introduced into the environment that adversely affects the usefulness of a resource or the health of humans, animals, or ecosystems.

Pollution :

Generally, the presence of a substance in the environment that, because of its chemical composition or quantity, prevents the functioning of natural processes and produces undesirable environmental and health effects. Under the Clean Water Act, for example, the term has been defined as the man-made or man-induced alteration of the physical, biological, chemical and radiological integrity of water and other media.

Pollution Prevention :

1. Techniques that eliminate waste prior to treatment, such as changing ingredients in a chemical reaction.

2. Identifying areas, processes and activities that create excessive waste products or pollutants in order to reduce or prevent them through alteration or elimination of a process.

3. The EPA has initiated a number of voluntary programs in which industrial or commercial "partners" join with the EPA in promoting activities that conserve energy, conserve and protect the water supply, reduce emissions or find ways of utilizing them as energy resources, and reduce the waste stream.

Post-consumer Material :

Any household or commercial product that has served its original, intended use.

Post-consumer Recycle Content :

A product composition that contains some percentage of material that has been reclaimed from the same or another end use at the end of its former, useful life.

Post-industrial Material :

Industrial manufacturing scrap or waste; also called pre-consumer material

Post-industrial Recycle Content :

A product composition that contains some percentage of manufacturing waste material that has been reclaimed from a process generating the same or a similar product. Also called pre-consumer recycle content.

Potable Water :

Water that is safe to drink.

Ppb :

Parts per billion.

Ppm :

Parts per million.

Prefabricated :

Standardized building sections that are created in a factory to be shipped and assembled in another location.

Precautionary Principle :

The principle that advises that, in the face of uncertainty, the best course of action is to assume that a potential problem is real and should be addressed ("better safe than sorry").

Particulate :

1. Fine dust or particles (i.e., smoke).

Prerequisites :

LEED Green Building Rating System component. Compliance is mandatory for achieving certification but does not count toward the accumulation of points.

Pyrolysis :

Decomposition of a chemical by extreme heat.

Radiant Heating :

An efficient heating system that warms cold objects, which then radiate heat into the surrounding space evenly.

Rainwater Harvesting :

The collection, storage, and reuse of rainwater.

(Rapidly) Renewable resource :

Organic materials, like bamboo or corn, that have a short regeneration period to full maturation, usually in stark contrast to the material they are replacing.

R-Value :

Measure of the resistance of a material to heat flow. The higher the number, the greater the resistance to heat flow.

Radiant Barrier :

A material that reflects radiant heat, typically a foil-faced or foil-like material used in roof systems. Used properly in some climates, it can reduce cooling requirements but has no positive effect on heating requirements.

Radon :

A radioactive gas that occurs naturally, but when trapped in buildings can cause health problems such as lung cancer.

Raised Floor :

In underfloor air distribution systems, a platform structure typically consisting of concrete-filled steel floor panels supported on pedestals 8 to 18 inches above the concrete structural floor slab. Each panel can be independently removed for access to the underfloor plenum containing the air delivery system, electrical cables, and other services.

Rapidly Renewable :

Materials that are not depleted when used. These materials are typically harvested from fast growing sources and do not require unnecessary chemical support. Examples include bamboo, flax, wheat, wool and certain types of wood.

Recharge Area :

An area where rainfall can infiltrate into an aquifer.

Re-circulated Air :

Return air that is diverted from the exhaust route, mixed with incoming outside air, conditioned, and delivered to the conditioned space. Recycling the air circulating through an HVAC system reduces energy requirements.

Reclamation :

Restoration of materials found in the waste stream to a beneficial use that may be other than the original use.

Re-commissioning :

Also called Tuning, a re-calibration of a facility's operating systems.

Recyclable :

Commonly referred to as the ability of a product or material to be recovered from, or otherwise diverted from, the solid waste stream for the purposes of recycling. FTC guidelines indicate that a product may not be advertised as "recyclable" unless a viable, active reclamation system exists, that is available to a majority of end users, and collects and processes the product for recycling.

Recycled Content :

Materials that have been recovered or otherwise diverted from the solid waste stream, either during the manufacturing process (pre-consumer), or after consumer use (post-consumer). Pre-consumer material does not include materials normally reused by industry within the original manufacturing process.

Recycling :

Process by which materials that would otherwise become solid waste are collected, separated or processed and returned to the economic mainstream to be reused in the form of raw materials or finished goods.

Refrigerant :

A liquid capable of vaporizing at a low temperature and used in AC systems.

Relative Humidity :

Ratio of the amount of water vapor in air at a specific temperature to the maximum capacity of the air at that temperature.

Remanufacturing :

A recycling concept by which an existing product has its useful life extended through a secondary manufacturing or refurbishing process such as remanufactured systems furniture.

Remediation :

Efforts to counteract some or all of the effects of pollution after it has been released into an environment.

Regeneration :

Renewal of sites or habitats that have become unfit for human, animal, or plant habitation, bringing them back into productive use. The term most commonly refers to urban and industrial land.

R-Value :

A measure of the thermal resistance of material, especially insulation.

Reclaim :

To use a product again after its initial use. This commonly refers to materials such as tile, brick, and stone.

Renewable Energy :

Energy resources, such as wind, solar, hydroelectric, biomass, geothermal, ocean thermal, and wave power, which replenish themselves within a short period. Although non-pollutive, some displace habitats and require large tracts of land.

Renewable Resources :

A resource that can be replenished at a rate equal to or greater than its rate of depletion; i.e., solar, wind, geothermal and biomass resources.

Requirements and Submittals :

LEED Green Building Rating System component that specifies the criteria to satisfy the prerequisites or credit, the total number of points available, and the documentation required for the LEED application.

Resource Conservation :

Practices that protect, preserve or renew natural resources in a manner that will ensure their highest economic or social benefits.

Resource Efficiency :

A practice in which the primary consideration of material use begins with the concept of "Reduce - Reuse - Recycle - Repair" stated in descending order of priority.

Respirable :

Particles or aerosols capable of being inhaled into the deep lung, < 3 microns in diameter.

Respirable Suspended Particles (RSP) :

Inhalable particulate matter in the air.

Retro-commissioning :

Commissioning performed on a facility that has been in service but not previously commissioned.

Reuse :

Using a product or component of municipal solid waste in its original form more than once.

Reused Components :

Structural or finish materials removed from old buildings and reused in new or remodeled buildings.

Reversible Disassembly :

Reverse manufacturing, in which the removal of screws, clips, and other fasteners permits refurbishment and reuse of some or all of the components and modules of a product.

Resource Conservation :

Practices that protect preserve or renew natural resources in a manner that will ensure their highest economic or social benefits.

Respirable :

Particles or aerosols capable of being inhaled into the deep lung, < 3 microns in diameter.

Reuse :

To use products, such as glass bottles or shipping crates, repeatedly in the same form.

Risk :

A measure of the probability of an adverse effect on a population under a well-defined exposure scenario.

Risk Assessment :

An evaluation of potential consequences to humans, wildlife, or the environment caused by a process, product, or activity, and including both the likelihood and the effects of an event.

Risk Factor :

Characteristics (i.e., race, sex, age, obesity) or variables (i.e., smoking, occupational exposure level) associated with increased probability of a toxic effect.

Sanitary Sewers :

Underground pipes that carry off only domestic or industrial waste, but not storm water.

Sanitary Survey :

An on-site review of the water sources, facilities, equipment, operation and maintenance of a public water system to evaluate the adequacy of those elements for producing and distributing safe drinking water.

Sanitary Water :

Water discharged from sinks, showers, kitchens or other nonindustrial operations, but not from commodes.

Scientific Certification Systems (SCS) :

An independent testing and certification organization who evaluates a wide variety of food safety and environmental claims. The company's environmental division certifies a wide variety of claims related to environmental achievement in the product manufacturing and natural resource extraction sectors. Specific product attributes, such as recycled content and biodegradability, may be certified under the environmental claims certification program. SCS can also certify more holistic claims of environmental prefer ability considering the full product life-cycle.

Scoping :

The involvement of local government agencies and the general public in the production of an Environmental Impact Statement for a proposed project.

Scrubbers :

Devices that cleanse emissions, usually with water, before they are released into the air.

Sealed Combustion Furnace :

Furnaces or boilers that draw air for combustion from outside the home directly onto the burner compartment and vent exhaust gases directly to the outside. The systems eliminate the possibility of back drafting.

Seasonal Energy Efficiency Ratio (SEER) :

The amount of cooling provided by a central air conditioner per unit of electricity purchased; SEER is tested over the entire cooling season, taking cycling into account. The higher the SEER number, the more efficient the air conditioner. SEER, in contrast to EER and COP, takes into account the efficiency losses resulting from system cycling.

Selective Cutting :

The harvesting of trees such that only certain trees are cut down and the land is not stripped bare.

Sick Building Syndrome (SBS) :

(1) A human health condition in which infections linger, caused by exposure to contaminants within a building as a result of poor ventilation.

(2) Building whose occupants experience acute health and/or comfort effects that appear to be linked to time spent therein, but where no specific illness or cause can be identified. Complaints may be localized in a particular room or zone, or may spread throughout the building and may abate on leaving the building. Also see "Building-related Illness."

Sink :

Place in the environment where a compound or material collects.

Site Preservation :

Minimizing the disruption of a building on its surrounding environment (reusing existing structures on a site, rather than building upon unused land; or avoiding building on top of environmentally fragile land that could interfere with natural ecosystems).

Sizing :

Calculation of the heat loss and heat gain for a building at "design temperatures" (those close to the maximum and minimum temperatures anticipated for a given location) in order to select heating and cooling equipment of sufficient capacity. Installing excess equipment capacity, or over sizing, is common but leads to inefficient operation and, for air conditioners, decreases the dehumidification. Calculations are most often done according to the ACCA Manual-J (or similar) procedure.

Slash and Burn Agriculture :

A form of agriculture where trees and other vegetation are cut down and burned in order to clear the land and release nutrients into the soil.

Smart House :

A home that consists of programmable electronic controls and sensors that can regulate heating, cooling, ventilation, lighting, and equipment operation in an energy conserving and climatically responsible manner.

Smog :

Traditionally, a mixture of smoke plus fog. Today, the term "smog" has the more general meaning of any anthropogenic haze. Photochemical smog involves the production, in stagnant, sunlit atmospheres, of oxidants such as O3 by the photolysis of NO2 and other substances, generally in combination with haze-causing particles.

Solar Energy :

Energy derived from the Sun.

Solar Heat Gain Coefficient (SHGC) :

An indicator of the amount of solar radiation admitted through and absorbed by a window and subsequently released as heat indoors. SHGC is expresses as a number between 0 and 1- the higher the number, the more solar heat the window transmits.

Solar Thermal Panels :

A device that collects energy from the sun and coverts it into heat for domestic water systems and/or space-heating systems.

Solar Water Heater :

Heat from the sun that is absorbed and then transferred by pumps to a storage unit, which is then transported to the hot water of a home through a heat exchanger.

Source Reduction :

1. The design, manufacture, purchase or use of materials to reduce the amount or toxicity of waste in an effort to reduce pollution and conserve resources (i.e., reusing items, minimizing the use of products containing hazardous compounds, extending the useful life of a product and reducing unneeded packaging).

2. Practices that reduce the amount of any hazardous substance, pollutant or contaminant entering any waste stream or otherwise being released into the environment. Such practices also reduce the risk to public health and the environment associated with such releases. Term includes equipment or technology modifications, substitution of raw materials, and improvements in housekeeping, maintenance, training or inventory control.

Stack Effect :

Flow of air resulting from warm air rising, creating a positive pressure area at the top of a building and negative pressure area at the bottom. This effect can overpower the mechanical system and disrupt building ventilation and air circulation.

Sterilizer :

One of three groups of antimicrobials registered by the EPA for public health uses. The EPA considers an antimicrobial to be a sterilizer when it destroys or eliminates all forms of bacteria, viruses, and fungi and their spores. Because spores are considered the most difficult form of microorganism to destroy, the EPA considers the term "sporicide" to be synonymous with "sterilizer."

Stratosphere :

The atmospheric shell lying just above the troposphere and characterized by a stable lapse rate. The temperature is approximately constant in the lower part of the stratosphere and increases from about 20 km to the top of the stratosphere at about 50 km.

Straw-Bale Construction :

The use of annually renewable agricultural waste product, such as wheat, oats, barley, rye, and rice, to build thick, super-insulated, stucco covered walls. Straw bales are traditionally a waste product which farmers do not till under the soil, but do sell as animal bedding or landscape supply. Straw is the dry plant material or stalk left in the field after a plant has matured, been harvested for seed, and is no longer alive. Bales can be taken directly from a baling machine or can be re-compressed for higher density. In contrast, hay bales are made from short species of livestock feed grass that is green/alive and is not suitable for this application.

Stressor :

A set of conditions that may lead to an undesirable impact on the living systems which occupy an environment.

Strip Mining :

A form of surface mining, especially for coal, that is very destructive to the landscape.

Structural Insulated Panel (SIP) :

Load bearing wall, roof, or floor panel made of foam sandwiched between two sheets of plywood or oriented strand board.

Suburban Sprawl :

The spreading of a city's population out into the surrounding countryside, forming suburbs.

Sulfur Dioxide (SO2) :

A heavy, smelly gas that can be condensed into a clear liquid; used to make sulfuric acid, bleaching agents, preservatives and refrigerants; a major source of air pollution in industrial areas.

Superfund :

A commonly used name for the Federal Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) - related to the cost and cleanup of hazardous waste sites (EPA's National Priorities List).

Sustainable :

Meeting the needs of the present without compromising the ability of future generations to meet their needs.

Sustainability :

The practice of meeting the needs of the present without depleting resources or harming natural cycles for future generations.

Sustainable Development :

An approach to progress that meets the needs of the present without compromising the ability of future generations to meet their needs.

Sustainability Gap :

The difference between ecological production and current human over-consumption. Developing sustainability means reducing the sustainability gap.

Sustainable Sites (SS) :

LEED Rating System category. Prerequisites and credits in this category focus on the selection of a LEED Certified Building and/or buildings that have incorporated key sustainability concepts and practices into design, construction, operations and maintenance activities.

Sustainable Yield vs. Ecologically Sustainable Forestry :

Sustainable yield forestry dictates that the same numbers of trees cut down are planted.

Technical Advisory Group (TAG) :

Subcommittees that consist of industry experts who assist in developing credit interpretations and technical improvements to the LEED system.

Technical Nutrient :

A material designed to return into the technical cycle.

Technosphere :

The portion of the biosphere which has been altered or influenced by human activity.

Teratogen :

Any agent, such as a virus, drug or radiation that can cause the malformation of an embryo or a fetus.

Thermal Bridge :

A conductive element, such as a metal channel, that bypasses a less conductive element, such as insulation.

Thermal Buffer :

A gap between a space and its exterior used to reduce the heating/cooling load.

Thermal By-pass :

An opening between spaces that air can move through, thereby violating air tightness.

Thermal Comfort :

The appropriate combination of temperature combined with airflow and humidity which allows one to be comfortable within the confines of a building.

Thermal Expansion :

The temporary increase in volume or linear dimensions of materials when heated.

Thermal Pollution :

The addition of heat to a body of water that may change the ecological balance

Thermal Shock :

The strain produced in a material due to sudden changes in temperature.

Threshold Limit Value (TLV) :

The concentration of an airborne substance to which an average person can be repeatedly exposed without adverse effects. TLVs may be expressed in three ways:

1. TLV-TWA-Time-weighted average, based on an allowable exposure averaged over a normal 8-hour workday or 40-hour workweek.

2. TLV-STEL-Short-term exposure limit, or maximum concentration for a brief specified period of time, depending on a specific chemical (TWA must still be met).

3. TLV-C-Ceiling exposure limit, or maximum exposure concentration not to be exceeded under any circumstances (TWA must still be met).

Thermal Pollution :

The addition of heat to a body of water that may change the ecological balance.

Tipping Fee :

Charge for the unloading or dumping of waste at a recycling facility, composting facility, landfill, transfer station or waste-to-energy facility.

Total Environmental Impact (TEI) :

Total change on the environment, whether adverse or beneficial, wholly or partially resulting from human activity, industry or natural disasters.

Total Environmental Impact (TEI) Index :

A tool developed and used by INVISTA Antron. Much broader than the traditional industrial measures of raw material consumption and emissions, the Total Environmental Impact (TEI) Index includes value recovery of waste materials, and has a measure of societal impact:

e.g., injuries and illnesses to employees and contractors; incidents like fires, explosions, accidental releases to the environment, and transportation incidents; global waste and emissions; and use of depletable raw materials and energy. The TEI Index was created using internal INVISTA studies in North America rationalized with published studies done by Boustead in Brussels and Potting & Blok in the Netherlands.

Total Volatile Organic Compounds :

The total mass, typically in milligrams per cubic meter, of the organic compounds collected in air.

Toxic :

Capable of having an adverse effect on an organism; poisonous; harmful or deadly.

Tree-Free Paper :

Paper made with alternative resources such as kenaf and hemp, without using virgin tree pulp.

Trichloroethylene :

A stable, low boiling-point colorless liquid, toxic if inhaled. Used as a solvent or metal degreasing agent, and in other industrial applications.

Triple Bottom Line Reporting :

New form of corporate disclosure which integrates financial, environmental and social reporting.

Troposphere :

The lowest layer of the atmosphere, ranging from the ground to the base of the stratosphere at 10-15 km altitude, depending on latitude and weather conditions. About 85% of the mass of the atmosphere is in the troposphere, where most weather features occur due to the dynamic interactions associated with temperature variations.

U-Value :

Measurement of the thermal conductivity of a material, or inverse of R-Value. The lower the U-Value, the greater resistance to heat flow (lower U-Value = Higher R-Value.)

Unconditioned Space :

Area within the outermost shell of a house that is not heated or cooled-the area outside of the thermal envelope. Such areas typically include crawlspaces, attics, and garages.

Underfloor Air Distribution :

A system using an underfloor plenum (open space between the structural concrete slab and the underside of a raised floor system) to deliver conditioned air directly into the occupied zone of the building. Air is delivered through supply outlets typically located at floor level or integrated as part of the office furniture and partitions. Return grilles are located above the occupied zone. This upward convection of warm air is used to efficiently remove heat loads and contaminants from the space.

Upcycling :

A term coined to describe the creation of a product with higher intrinsic value, manufactured from a material at the end of its service life, which had a lower initial end use value. It is important to note that the term as currently used, does not provide insight into environmental benefit (e.g. there may actually be less environmental benefit to upcycling if energy used to upcycle is more than recycling back to the same product).

Upstream Impacts :

Environmental impacts that are caused by the extraction of raw materials, transportation, and the manufacturing process.

Upcycling :

A term coined to describe the creation of a product with higher intrinsic value, manufactured from a material at the end of its service life, which had a lower initial end use value. It is important to note that the term as currently used, does not provide insight into environmental benefit (e.g. there may actually be less environmental benefit to upcycling if energy used to upcycle is more than recycling back to the same product).

Urban Heat Island :

The increase in ambient temperature that occurs in cities because paved areas and buildings absorb more heat from the sun than natural landscape and additional heat is generated by vehicles, lighting, and other equipment.

Urban Ore :

The concept that wastes of today, such as materials disposed of in landfills, may serve as sources of valuable raw materials, such as metals, in the future.

Urethanes :

A family of plastics (polyurethane's) used for varnish coatings, foamed insulations, highly durable paints, and rubber goods.

USGBC (U.S. Green Building Council) :

The United States foremost coalition of leaders from across the building industry working to promote buildings that are environmentally responsible, profitable, and healthy places to live and work.

USGBC (United States Green Building Council) :

A non-profit organization committed to expanding sustainable building practices. The USGBC is composed of more than 12,000 organizations from across the building industry that are working to advance structures that are environmentally sustainable, profitable, and healthy places to live and work. Members includes building owners, real estate developers, facility managers, architects, designers, engineers, general contractors, subcontractors, product and building system manufacturers, government agencies, and nonprofit organizations.

Value Recovery :

Redirecting materials typically targeted for landfill or incineration into useful end use products; energy could be one of those products. See "Reclamation."

Ventilation :

Process by which outside air is conveyed to an indoor space.

Ventilation Effectiveness :

The system's ability to remove pollutants generated by internal sources in a space, zone, or building. In comparison, air change effectiveness describes the ability of an air distribution system to ventilate a space, zone, or building.

Volatile :

Any substance that evaporates readily.

Ventilated Façade :

A special type of curtain wall that consists of two glazed facades separated by a gap through which ambient air is allowed to flow.

Volatile Organic Compound (VOC) :

Any organic compound that evaporates at room temperatures and is hazardous to human health, causing poor indoor air quality. Many VOCs found in homes, such as paint strippers and wood preservatives, contribute to sick building syndrome because of their high vapor pressure. VOCs are often used in paint, carpet backing, plastics, and cosmetics. The United States Environmental Protection Agency (EPA) has found concentrations of VOCs in indoor air to be, on average, two to five times greater than in outdoor air. During certain activities, indoor levels of VOCs may reach 1,000 times that of the outside air.

Waste Reduction :

Using source reduction, recycling, or composting to prevent or reduce waste generation.

Waste Stream :

The total flow of solid waste from homes, businesses, institutions and manufacturing that is recycled, burned or disposed of in landfills, or segments thereof such as the "residential waste stream" or the "recyclable waste stream."

Waste to Energy :

Burning of industrial waste to provide steam, heat or electricity. Sometimes referred to as waste-to-fuel process.

Wastewater :

The spent or used water from a home, community, farm, or industry that contains dissolved or suspended matter.

Water Efficiency (WE) :

LEED Rating System category. Prerequisites and credits in this category focus on the water efficiency of a building/interior.

Wildscaping :

Retention of native soil, vegetation, and other natural features when building on the land, rather than the removal of soil, vegetation and natural features followed by artificial landscaping once the building is completed.

Wind Farm :

A vast trace of land covered with wind-powered turbines that are used to drive generators that produce electricity.

Wind Power :

The harnessing of the wind's energy for human applications.

Waste to Energy :

Burning of industrial waste to provide steam, heat or electricity. Sometimes referred to as waste-to-fuel process.

Wind Power :

The conversion of energy from the wind into electricity. Surplus electricity is often stored in a battery storage system for later use, or the power is passed back to the utility, making the electric meter turn in reverse.

Xeriscaping :

Landscaping designed to save water.

Xylene :

Found in paints, varnishes, lacquers, solvents, xylenes are included in the formulations of paints, adhesives, and some furniture products, and are observed off-gassing.

Zero-Carbon Buildings :

There are no emissions of carbon dioxide at all from any of the systems and appliances in these structures.

Zero Energy Building (ZEB) :

A building with a net energy consumption of zero over a typical year because the energy provided by on-site renewable energy sources is equal to the energy used. Buildings approaching this goal may be called near zero energy buildings or ultra-low energy buildings.

Zone :

A space or group of spaces in a building having similar heating and cooling requirements throughout its occupied area, so that comfort conditions may be controlled by a single temperature sensor with corresponding controller.

Zoning :

The practice of dividing a building into smaller zones for increased comfort control by the HVAC system.