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Government Glossary



Acid Rain — Rain (and snow) that contains a heavy concentration of sulfuric and nitric acids. Acid rain can contaminate lakes, rivers, and streams; harm wildlife; damage crops; and corrode buildings and other structures.

Air Pollutant — Any natural or artificial substance in air that could, in high enough concentration, harm humans, animals, vegetation, or material. Air pollutants can be in the form of solid particles, liquid droplets, gases, or any combination thereof.

Air Quality Standards — Standards set by law that may not be exceeded for selected pollutants in ambient air. These standards set limits on the amount of pollutants that industries and motor vehicles can emit.

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Best Available Control Technology (BACT) — Technology that meets or exceeds the most current technology available to reduce or minimize pollution. BACT is required under the federal New Source Review (NSR) permitting program to ensure that new or modified power plants, industrial boilers, and factories will be as clean as possible and won’t significantly worsen air quality.

Biomass Energy — Energy derived from wood, wood wastes, other organic wastes, landfill gas, and animal and human wastes.

Brownfields — A property whose expansion, redevelopment, or reuse is complicated by actual or potential environmental contamination.

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Cap and Trade — A regulatory system that imposes a mandatory cap on greenhouse gas emissions and provides a market-based swapping system in which allowances to emit additional pollutants are traded. See also “Waxman-Markey Bill.”

Carbon Dioxide (CO2) — An odorless, colorless greenhouse gas created by burning fossil fuels (coal, oil, and natural gas), solid waste, trees, and wood products. It is also created by some chemical reactions, such as the manufacture of cement. Human-generated CO2 makes up about 80 percent of all human-made greenhouse gas emissions and is the main cause of climate change.

Carbon Dioxide Equivalent — A measure used to compare the emissions from various greenhouse gases based on their global warming potential (GWP). Carbon dioxide equivalents are commonly expressed as "tons of carbon dioxide equivalents." The carbon dioxide equivalent for a gas is derived by multiplying the tons of the gas by the associated GWP.

Carbon Footprint — A measure of the impact human activities have on the environment in terms of the amount of greenhouse gases produced, measured in units of carbon dioxide equivalents.

Carbon Sequestration — The removal of carbon dioxide from the atmosphere. Trees and plants, for example, absorb carbon dioxide, release oxygen, and store the carbon. Fossil fuels (coal, oil, and natural gas) were at one time biomass and continue to store the carbon until burned.

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

Climate Change — Any significant change in measures of climate, such as temperature, precipitation, or wind, lasting for an extended period (decades or longer). Climate change may result from:

  • Natural factors, such as changes in the sun's intensity or slow changes in the Earth's orbit around the sun.
  • Natural processes within the climate system (e.g., changes in ocean circulation).
  • Human activities that change the atmosphere's composition (e.g., through burning fossil fuels) and the land surface (e.g., deforestation, afforestation, urbanization, and desertification).
  • See also "Global Warming."

Closed-loop Recycling — When a used product is recycled into a similar product; a recycling system in which a particular mass of material is remanufactured into the same product (e.g., glass bottles into glass bottles).

Cogeneration — The use of a heat engine or a power station to simultaneously generate both electricity and useful heat.

Compact Fluorescent Lightbulb (CFL) — An efficient form of lighting that uses 75 percent less electricity than a standard bulb and lasts up to 10 times longer.

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Deforestation — Practices or processes that result in the conversion of forested lands for nonforest uses. Deforestation is one of the major causes of climate change because the burning or decomposition of the wood releases carbon dioxide, and trees that once removed carbon dioxide from the atmosphere are no longer present.

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.

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Ecosystem — An interconnected and symbiotic grouping of animals, plants, fungi, and microorganisms that sustains life through biological, geological, and chemical activity.

Emission Controls — Any measures that reduce 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.

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

Energy Efficiency Ratio (EER) — The energy output of an appliance related to its energy consumption. The higher the number, the more efficient the appliance.

EnergyGuide Label — A yellow label on most new appliances that tells you how much electricity the appliance uses and estimates how much it will cost to operate. The EnergyGuide label helps compare the efficiency of different major appliances. More information about the EnergyGuide label is available at www1.eere.energy.gov/consumer/tips/shopping_guide.html.

ENERGY STAR® — A joint program of the U.S. Environmental Protection Agency and the U.S. Department of Energy that identifies energy efficient products and practices. ENERGY STAR-qualified appliances use 10 to 50 percent less electricity than standard models. A list of ENERGY STAR-qualified products is available at www.energystar.gov.

Environmental Footprint — The environmental impact of a company or other industrial entity 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.

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Fossil Fuel — Coal, oil, and natural gas: fuels derived from long-buried decomposed plants and animals. Fossil fuels provide more than 85 percent of all the energy consumed in the United States, nearly two-thirds of our electricity, and virtually all of our transportation fuels. Burning fossil fuels creates greenhouse gases, the principal cause of global warming and climate change.

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Geothermal Power — Electricity derived from heat found under the Earth’s surface. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma. Geothermal power is clean and sustainable.

Global Warming — An average increase in the temperature of the atmosphere near the Earth's surface, which can contribute to changes in global climate patterns. Global warming has a variety of causes, both natural and human induced, but most often refers to the warming caused by human-generated greenhouse gas emissions. See also "Climate Change."

Green Power — Electricity generated from renewable sources such as wind, sun, water, or biomass. Generating green power doesn’t produce greenhouse gases.

Green Roof — A roofing system that consists of vegetation and soil, or a growing medium, planted over a waterproofing membrane. Green roofs can be used in many applications, including industrial facilities, residences, and offices. They are widely used for their storm-water management and energy-savings potential, as well as their aesthetic benefits.

Greenhouse Effect — The warming of the Earth's atmosphere as a result of carbon dioxide and other greenhouse gases in the atmosphere. A natural phenomenon that makes life possible on Earth, the greenhouse effect is exacerbated by the increase in human-generated greenhouse gases, particularly carbon dioxide. Human-generated greenhouse gases are the main cause of climate change.

Greenhouse Gas (GHG) — Any gas that traps heat in the atmosphere. The main GHGs caused by human activities are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). Human-generated GHGs – particularly CO2, which makes up about 80 percent of all human-made GHG emissions – are the main cause of climate change.

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Heat Pumps — Heat pumps extract heat from either the air or ground and transfer that heat by circulating a refrigerant through a cycle of alternating evaporation and condensation. The cycle can be reversed for cooling. The efficiency of an air-source heat pump varies tremendously with climate, while ground-source heat pumps take advantage of stable ground temperatures to deliver consistent performance. A heat pump is generally twice as efficient as a standard furnace.

Hydrofluorocarbons (HFCs) — Powerful greenhouse gases emitted as by-products of industrial processes and used in manufacturing. HFCs, perfluorocarbons (PFCs), and sulfur hexafluoride (SF6) are fluorinated gases that are sometimes called high global warming potential (GWP) gases because of their potency.

Hydroelectric Power — Electricity generated by falling water.

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Intergovernmental Panel on Climate Change (IPCC) — A scientific body established by the United Nations Environment Program and the World Meteorological Organization to provide objective information about climate change. The IPCC assesses the latest scientific, technical, and socioeconomic literature produced worldwide relevant to climate change. Hundreds of scientists all over the world contribute to the work of the IPCC as authors, contributors, and reviewers. More information is available at www.ipcc.ch.

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Methane (CH4) — A colorless, nonpoisonous, flammable greenhouse gas emitted during the production and transportation of fossil fuels (coal, natural gas, and oil). Livestock and other agricultural practices and the decay of organic waste in municipal solid waste landfills also emit methane.

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Nuclear Power — Electricity generated using uranium fuel, consisting of solid ceramic pellets, through a process called fission. Nuclear power does not produce greenhouse gas emissions but does produce highly toxic radioactive wastes.

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Ozone Layer — The protective layer in the atmosphere about 12 to 15 miles above sea level that absorbs some of the sun's ultraviolet (UV) rays and reduces the amount of potentially harmful radiation that reaches the Earth's surface.

Ozone — A gas that occurs both in the Earth's upper atmosphere and at ground level. Ground-level ozone is an air pollutant that is harmful to breathe and damages crops, trees, and other vegetation. It is a main ingredient in smog. The stratosphere or "good" ozone layer extends upward from about six to 30 miles and protects life on Earth from the sun's harmful ultraviolet (UV) rays.

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Petroleum — A fossil fuel, also called oil, 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.

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

Photovoltaic (PV) — A technology that converts light directly into electricity.

Pollution Prevention — Reducing or eliminating waste at the source by modifying production processes, promoting the use of nontoxic or less toxic substances, implementing conservation techniques, and reusing materials rather than putting them into the waste stream.

Propane — A normally gaseous hydrocarbon; a colorless paraffin gas that boils at a temperature of 143.67 degrees Fahrenheit. It is extracted from natural gas or refinery gas streams and used for home heating and cooking.

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Recycling — A 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.

Renewable Resource — A resource that can be replenished at a rate equal to or greater than its rate of depletion; nonfossil fuels such as solar, wind, hydro, geothermal and biomass, and water.

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

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Sulfur Dioxide (SO2) — A heavy, malodorous 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 resulting from combustion of coal and oil.

Sulfur Hexafluoride (SF6) — A colorless, powerful greenhouse gas used primarily in electrical transmission and distribution systems as a dielectric medium. SF6, hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs) are fluorinated gases that are sometimes called high global warming potential (GWP) gases because of their potency.

Sustainability — Practices that would ensure the continued viability of a product or action well into the future.

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

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Waxman-Markey Bill — The American Clean Energy and Security Act of 2009 authored by Representatives Henry Waxman of California and Ed Markey of Massachusetts that would, among other things, would establish a cap-and-trade system and mandate that 15 percent of the nation's electricity come from renewable sources of energy by 2020.

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