| Term |
Meaning |
|
| Abatement |
The reduction or elimination of pollution. |
|
| Acute Exposure |
One or a series of short-term exposures generally lasting less than 24 hours. |
|
| Acute Health Effect |
A health effect that occurs over a relatively short period of time, such as minutes
or hours. |
|
| Adverse Health Effect |
A health effect from exposure to air contaminants that may range from relatively
mild temporary conditions, such as eye or throat irritation, shortness of breath, or
headaches to permanent and serious conditions, such as birth defects, cancer or damage
to lungs, nerves, heart, liver or other internal organs. |
|
| Afterburner |
An air pollution abatement device that removes undesirable organic gases
through incineration. |
|
| Air Monitoring |
Sampling for and measuring of pollutants present in the atmosphere. |
|
| Air Pollutants |
Amounts of foreign and/or natural substances occurring in the atmosphere that may
result in adverse effects to humans, animals, vegetation, and other materials. |
|
| Air Quality Index |
A numerical index used for reporting severity of air pollution levels to the public. |
|
| Alternative Fuels |
Fuels such as methanol, ethanol, natural gas, and liquid petroleum gas that are
cleaner burning. |
|
| Ambient Air |
Air that is accessible to the public, also referred to as outdoor air. |
|
| Asbestos |
A mineral fiber that can pollute air or water and cause cancer or asbestosis when
inhaled. |
|
| Asthma |
A chronic inflammatory disorder of the lungs characterized by wheezing, shortness
of breath, chest tightness, and cough. |
|
| Atmosphere |
The gaseous mass or envelope of air surrounding the Earth. |
|
| Attainment Area |
a specifically designated area that is within the EPA established limits for
the six criteria pollutants. |
|
| Baghouse |
An air pollution control device that traps particulates by forcing gas streams
through large permeable bags usually made of glass fibers. |
|
| Best Available Control Measure |
A term used to describe the best measures for controlling small or
dispersed sources of particulate matter and other emissions from sources such as
roadway dust, woodstoves, and open burning. |
|
| Best Available Control Technology |
The most up-to-date methods, systems, techniques, and production processes
available to achieve the greatest feasible emission reductions for given regulated
air pollutants and processes |
|
| Carbon Monoxide |
a criteria pollutant. It replaces oxygen in the bloodstream, aggravates heart
disease, and impairs alertness. |
|
| CAS Registry Number |
The Chemical Abstracts Service Registry Number is a numeric designation assigned
by the American Chemical Society's Chemical Abstract Service and uniquely identifies
a specific compound. This entry allows one to conclusively identify a material
regardless of the name or naming system used. |
|
| Chlorofluorocarbons |
Any of a number of substances consisting of chlorine, fluorine, and carbon. CFCs
are used for refrigeration, foam packing, solvents, and propellents |
|
| Chronic Exposure |
Long-term exposure, usually lasting one year to a lifetime. |
|
| Chronic Health Affect |
A health effect that occurs over a relatively long period of time, such as months
or years. |
|
| Clean Fuels |
Low-pollution fuels that can replace ordinary gasoline, including gasohol, natural
gas, and propane. |
|
| Criteria Pollutant |
EPA uses six "criteria pollutants" as indicators of air quality, and
has established for each of them a maximum concentration above which adverse effects
on human health may occur. These threshold concentrations are called National
Ambient Air Quality Standards (NAAQS). The criteria pollutants are ozone, carbon
monoxide, nitrogen dioxide, sulfur dioxide, particulate matter and lead. |
|
| Diesel Engine |
A type of internal combustion engine that uses low-volatility petroleum fuel and
fuel injectors and initiates combustion using compression ignition (as opposed to spark
ignition that is used with gasoline engines). |
|
| Electric Vehicle |
A motor vehicle that uses an electric motor as the basis of its operation. |
|
| Emissions |
Release of pollutants into the air from a source. |
|
| Ethanol |
Ethyl-alcohol, a volatile alcohol containing two carbon groups
(CH3CH2OH). For fuel use, ethanol is produced by fermentation of
corn or other plant products. |
|
| Exceedance |
A measured level of an air pollutant higher than the national or state ambient air
quality standards. |
|
| Exposure |
The concentration of the pollutant in the air multiplied by the population exposed
to that concentration over a specified time period. |
|
| Fine Particles |
Particulate matter with an aerodynamic diameter of 2.5 microns or less. |
|
| Flexible Fuel Vehicle |
Vehicles that can use a combination of fuels such as alcohol fuel and unleaded
gasoline. |
|
| Fossil Fuels |
Fuels such as coal, oil, and natural gas; so-called because they are the remains of
ancient plant and animal life. |
|
| Fuel Cell |
An electrochemical cell which captures the electrical energy of a chemical reaction
between fuels such as liquid hydrogen and liquid oxygen and converts it directly and
continuously into energy of a direct electrical current. |
|
| Global Warming |
An increase in the temperature of the Earth's troposphere, the section of the
atmosphere closest to the Earth's surface. |
|
| Greenhouse Effect |
The warming effect of the Earth's atmosphere. Light energy from the sun which passes
through the Earth's atmosphere is absorbed by the Earth's surface and re-radiated into
the atmosphere as heat energy. The heat energy is then trapped by the atmosphere,
creating a situation similar to that which occurs in a car with its windows rolled up. |
|
| Greenhouse Gases |
Atmospheric gases such as carbon dioxide, methane, chlorofluorocarbons, nitrous
oxide, ozone, and water vapor that slow the passage of re-radiated heat through
the Earth's atmosphere. |
|
| Hazardous Air Pollutants |
Airborne chemicals that cause serious health and environmental effects. |
|
| Haze |
A phenomenon that results in reduced visibility due to the scattering of light
caused by aerosols. Haze is caused in large part by man-made air pollutants. |
|
| Hybrid Electric Vehicle |
Hybrid electric motor vehicles may operate using both electric and gas-powered
motors. |
|
| Incineration |
The act of burning a material to ashes. |
|
| Indoor Air Pollution |
Air pollutants that occur within buildings or other enclosed spaces, as opposed to
those occurring in outdoor, or ambient air. |
|
| Industrial Source |
Any of a large number of sources -- such as manufacturing operations, oil and gas
refineries, food processing plants, and energy generating facilities --that emit
substances into the atmosphere. |
|
| Internal Combustion Engine |
An engine in which both the heat energy and the ensuing mechanical energy are
produced inside the engine. This includes gas turbines, spark ignition gas, and
compression ignition diesel engines. |
|
| Inversion |
A layer of warm air in the atmosphere that prevents the rise of cooling air
and traps pollutants beneath it. |
|
| Lead |
a criteria pollutant. It increases risk of harm to central nervous system,
especially in children. |
|
| Maximum Achievable Control Technology |
Federal emissions limitations based on the best demonstrated control technology
or practices in similar sources to be applied to major sources emitting one or more
federal hazardous air pollutants. |
|
| Micron |
a unit of length equal to one millionth of a meter; the unit of measure for
wavelength. |
|
| National Ambient Air Quality Standards |
Standards established by the United States EPA that apply for outdoor air throughout
the country. There are two types of NAAQS. Primary standards set limits to protect public
health and secondary standards set limits to protect public welfare. |
|
| National Emission Standards for Hazardous Air Pollutants |
Emissions standards set by the U.S. EPA for a hazardous air pollutant, such as
benzene, which may cause an increase in deaths or in serious, irreversible, or
incapacitating illness. |
|
| Natural Sources |
Non-manmade emission sources, including biological and geological sources,
wildfires, and windblown dust. |
|
| New Source Performance Standard |
Uniform national EPA air emission standards that limit the amount of pollution
allowed from new sources or from modified existing sources. |
|
| New Source Review |
A Clean Air Act requirement that State Implementation Plans must include a
permit review, which applies to the construction and operation of new and modified
stationary sources in nonattainment areas, to ensure attainment of national
ambient air quality standards. |
|
| Nitrogen Oxides |
a criteria pollutant. It impairs breathing, increases lung infections, and worsens
lung diseases. |
|
| Nonattainment Area |
a specifically designated area that exceeds the EPA established limits for one or
more criteria pollutants. The designated area can be in attainment for some pollutants
while in non-attainment for others at the same time. |
|
| Non-Industrial Sources |
Any of a large number of sources -- such as mobile, area-wide, indirect, and
natural sources -- which emit substances into the atmosphere. |
|
| Opacity |
The amount of light obscured by particle pollution in the atmosphere. Opacity is
used as an indicator of changes in performance of particulate control systems. |
|
| Oxides of Sulfur |
a criteria pollutant. It irritates lung pathways which can increase lung infections,
asthma attacks, and worsen diseases. |
|
| Ozone |
a criteria pollutant. It irritates the eyes, nose, and throat, increases asthma
attacks, and impairs athletic performance. |
|
| Ozone Depletion |
The reduction in the stratospheric ozone layer. Stratospheric ozone shields the
Earth from ultraviolet radiation. |
|
| Ozone Layer |
A layer of ozone in the lower portion of the stratosphere -- 12 to 15 miles
above the Earth's surface -- which helps to filter out harmful ultraviolet rays
from the sun. It may be contrasted with the ozone component of photochemical smog
near the Earth's surface which is harmful. |
|
| Particulate Matter |
A criteria pollutant. It causes increased respiratory symptoms, decreases lung
function, aggravates asthma, can cause development of chronic bronchitis, irregular
heartbeat, non-fatal heart attacks, and premature death in those with heart
and lung diseases. |
|
| Photochemical |
Any chemical reaction which is initiated by light |
|
| Plume |
Airborne emissions from a specified source and the path through the atmosphere
of these emissions. |
|
| Point Sources |
Specific points of origin where pollutants are emitted into the atmosphere such as
factory smokestacks. |
|
| Prevention of Significant Deterioration |
A permitting program for new and modified stationary sources of air pollution
located in an area that attains or is unclassified for national ambient air
quality standards. |
|
| Primary Particles |
Particles that are directly emitted from combustion and fugitive dust sources. |
|
| Propellent |
A gas with a high vapor pressure used to force formulations out of aerosol
spray cans. Among the gases used are butanes, propanes, and nitrogen. |
|
| Radon |
A colorless, odorless, naturally occurring, radioactive, inert gaseous element
formed by radioactive decay of radium atoms in soil or rocks. |
|
| Reasonably Available Control Measures |
A broadly defined term referring to technologies and other measures that can be
used to control pollution. They include Reasonably Available Control Technology
and other measures |
|
| Reasonably Available Control Technology |
Control techniques defined in EPA guidelines for limiting emissions from existing
sources in nonattainment areas. RACTs are adopted and implemented by states. |
|
| Risk Management |
An evaluation of the need for and feasibility of reducing risk. |
|
| Secondary Particle |
Particles that are formed in the atmosphere. |
|
| Sensitive Groups |
Identifiable subsets of the general population that are at greater risk than
the general population to the toxic effects of a specific air pollutant. |
|
| Smog |
A combination of smoke and other particulates, ozone, hydrocarbons, nitrogen
oxides, and other chemically reactive compounds which, under certain conditions of
weather and sunlight, may result in a murky brown haze that causes adverse
health effects. The primary source of smog is usually motor vehicles. |
|
| Source |
Any place or object from which air pollutants are released. |
|
| State Implementation Plan |
A detailed description of the measures a state will use to carry out its
responsibilities under the Clean Air Act. |
|
| Surface Layer |
A concentration of air pollution that extends from the ground to an elevation
where the top edge of a pollution layer is visible. |
|
| Total Suspended Particulates |
Total particulate matter in a sample of ambient air. |
|
| Viscosity |
The degree to which a fluid resists flow under an applied force. |
|
| Volatile |
Any substance that evaporates readily. |
|
| Volatile Organic Compounds |
Carbon-containing compounds that evaporate into the air (with a few exceptions).
VOCs contribute to the formation of smog and/or may themselves be toxic. VOCs often
have an odor, and some examples include gasoline, alcohol, and the solvents used
in paints. |
|
| Zero Emission Vehicle |
Vehicles which produce no emissions from the on-board source of power, such as
an electric vehicle. |
|
