Acid rain -- Air pollution
produced when acid chemicals are incorporated into rain, snow, fog or mist.
The "acid" in acid rain comes from sulfur oxides and nitrogen
oxides, products of burning coal and other fuels and from certain industrial
processes. The sulfur oxides and nitrogen oxides are related to two strong
acids: sulfuric acid and nitric acid. When sulfur dioxide and nitrogen oxides
are released from power plants and other sources, winds blow them far
from their source. If the acid chemicals in the air are blown into areas where
the weather is wet, the acids can fall to Earth in the rain, snow, fog or
mist. In areas where the weather is dry, the acid chemicals may become
incorporated into dusts or smokes. Acid rain can damage the environment. human
health and property.
Alternative fuels -- Fuels
that can replace ordinary gasoline. Alternative fuels may have particularly
desirable energy efficiency and pollution reduction features.
Alternative fuels include compressed natural gas, alcohols, liquefied
petroleum gas (LPG), and electricity. The 1990 Clean Air Act encourages
development and sale of alternative fuels.
Attainment area -- A
geographic area in which levels of a criteria air pollutant meet the
health-based primary standard (national ambient air quality standard, or NAAQS)
for the pollutant. An area may have on acceptable level for one criteria air
pollutant, but may have unacceptable levels for others. Thus, an area could be
both attainment and nonattainment at the same time. Attainment areas are
defined using federal pollutant limits set by EPA.
Carbon monoxide (CO) -- A
colorless, odorless, poisonous gas, produced by incomplete burning of
carbon-based fuels. including gasoline, oil and wood. Carbon monoxide is also
produced from incomplete combustion of many natural and synthetic
products. For instance, cigarette smoke contains carbon monoxide. When carbon
monoxide gets into the body, the carbon monoxide combines with chemicals in
the blood and prevents the blood from bringing oxygen to cells, tissues and
organs. The body's parts need oxygen for energy, so high-level exposures to
carbon monoxide can cause serious health effects, with death possible from
massive exposures. Symptoms of exposure to carbon monoxide can include vision
problems, reduced alertness, and general reduction in mental and physical
functions. Carbon monoxide exposures are especially harmful to people with
heart, lung and circulatory system diseases.
CFCs (chlorofluorocarbons)
-- These chemicals and some related chemicals have been used in great
quantities in industry, for refrigeration and air conditioning, and in
consumer products. CFCs and their relatives, when released into the air, rise
into the stratosphere, a layer of the atmosphere high above the Earth.
In the stratosphere, CFCs and their relatives take part in chemical reactions
which result in reduction of the stratospheric ozone layer, which
protects the Earth's surface from harmful effects of radiation from the sun.
The 1990 Clean Air Act includes provisions for reducing releases
(emissions) and eliminating production and use of these ozone-destroying
chemicals.
Clean Air Act -- The
original Clean Air Act was passed in 1963, but our national air pollution
control program is actually based on the 1970 version of the law. The 1990
Clean Air Act Amendments are the most far-reaching revisions of the 1970 law.
In this summary, we refer to the 1990 amendments as the 1990 Clean Air Act.
Clean fuels --
Low-pollution fuels that can replace ordinary gasoline. These are alternative
fuels, including gasohol (gasoline-alcohol mixtures), natural gas and LPG
(liquefied petroleum gas).
Combustion -- burning.
Many important pollutants, such as sulfur dioxide, nitrogen oxides,
and particulates (PM-10) are combustion products, often products of the
burning of fuels such as coal, oil, gas and wood.
Continuous emission monitoring
systems (CEMS) -- machines which measure, on a continuous basis, pollutants
released by a source. The 1990 Clean Air Act requires continuous
emission monitoring systems for certain large sources.
Control technology; control
measures -- equipment, processes or actions used to reduce air
pollution. The extent of pollution reduction varies among technologies and
measures. In general, control technologies and measures that do the best job
of reducing pollution will be required in the areas with the worst pollution.
For example, the best available control technology/best available control
measures (BACT,BACM) will be required in serious nonattainment areas
for particulates, a criteria air pollutant. A similar high level
of pollution reduction will be achieved with maximum achievable control
technology (MACT) which will be required for sources releasing hazardous
air pollutants.
Criteria air pollutants --
a group of very common air pollutants regulated by EPA on the basis of
criteria (information on health and/or environmental effects of pollution).
Criteria air pollutants are widely distributed all over the country.
Curtailment programs --
restrictions on operation of fireplaces and woodstoves in areas where these
home heat sources make major contributions to pollution.
Emission -- release of pollutants
into the air from a source. We say sources emit pollutants. Continuous
emission monitoring systems (CEMS) are machines which some large sources
are required to install, to make continuous measurements of pollutant release.
Enforcement -- the legal
methods used to make polluters obey the Clean Air Act. Enforcement
methods include citations of polluters for violations of the law (citations
are much like traffic tickets), fines and even jail terms. EPA and the state
and local governments are responsible for enforcement of the Clean Air Act,
but if they don't enforce the law, members of the public can sue EPA or the
states to get action. Citizens can also sue violating sources, apart
from any action EPA or state or local governments have taken. Before the 1990 Clean
Air Act, all enforcement actions had to be handled through the courts. The
1990 Clean Air Act gave EPA authority so that, in some cases, EPA can
fine violators without going to court first. The purpose of this new authority
is to speed up violating sources' compliance with the law and reduce court
time and cost.
Hazardous air pollutants (HAPs)
-- chemicals that cause serious health and environmental effects. Health
effects include cancer, birth defects, nervous system problems and death due
to massive accidental releases such as occurred at the pesticide plant in
Bhopal, India. Hazardous air pollutants are released by sources such as
chemical plants, dry cleaners, printing plants, and motor vehicles (cars,
trucks, buses, etc.)
Inspection and maintenance program
(I/M program) -- Auto inspection programs are required for some polluted
areas. These periodic inspections, usually done once a year or once every two
years, check whether a car is being maintained to keep pollution down
and whether emission control systems are working properly. Vehicles which do
not pass inspection must be repaired. As of 1992, 111 urban areas in 35 states
already had I/M programs. Under the 1990 Clean Air Act, some especially
polluted areas will have to have enhanced inspection and maintenance
programs, using special machines that can check for such things as how
much pollution a car produces during actual driving conditions.
International air pollution
-- Canada and Mexico, the United States' neighbors, share the air at our
borders. Pollution moves across the national borders; this
international pollution can be serious. The 1990 Clean Air Act includes
provisions for cooperative efforts to reduce pollution that originates in one
country and affects another.
Interstate air pollution
-- In many areas, two or more states share the same air. We say these states
are in the same air basin defined by geography and wind patterns. Often, air pollution
moves out of the state in which it is produced into another state. Some
pollutants, such as the power plant combustion products that cause acid
rain, may travel over several states before affecting health, the
environment and property. The 1990 Clean Air Act includes many
provisions, such as interstate compacts, to help states work together to
protect the air they share. Reducing interstate air pollution is very
important since many Americans live and work in areas where more than one
state is part of a single metropolitan area.
Material safety data sheets (MSDS)
-- product safety information sheets prepared by manufacturers and marketers
of products containing toxic chemicals. These sheets can be obtained by
requesting them from the manufacturer or marketer. Some stores, such as
hardware stores, may have material safety data sheets on hand for products
they sell.
Mobile sources -- moving
objects that release pollution; mobile sources include cars, trucks,
buses, planes, trains, motorcycles and gasoline-powered lawn mowers. Mobile
sources are divided into two groups: road vehicles, which includes cars,
trucks and buses, and non-road vehicles, which includes trains, planes and
lawn mowers.
Monitoring (monitor)
Measurement of air pollution is referred to as monitoring. EPA, state
and local agencies measure the types and amounts of pollutants in community
air. The 1990 Clean Air Act requires certain large polluters to perform
enhanced monitoring to provide an accurate picture of their pollutant
releases. Enhanced monitoring programs may include keeping records on
materials used by the source, periodic inspections, and installation of
continuous emission monitoring systems (CEMS). Continuous emission
monitoring systems will measure, on a continuous basis, how much pollution is
being released into the air. The 1990 Clean Air Act requires states to
monitor community air in polluted areas to check on whether the areas are
being cleaned up according to schedules set out in the law.
Nitrogen oxides (NOx) -- a
criteria air pollutant. Nitrogen oxides are produced from burning
fuels, including gasoline and coal. Nitrogen oxides are smogformers, which
react with volatile organic compounds to form smog. Nitrogen oxides are also
major components of acid rain.
Nonattainment area -- a
geographic area in which the level of a criteria air pollutant is
higher than the level allowed by the federal standards. A single geographic
area may have acceptable levels of one criteria air pollutant but unacceptable
levels of one or more other criteria air pollutants; thus, an area can be both
attainment and nonattainment at the same time. It has been estimated that 60%
of Americans live in nonattainment areas.
Offset -- a method used in
the 1990 Clean Air Act to give companies which own or operate large
(major) sources in nonattainment areas flexibility in meeting
overall pollution reduction requirements when changing production processes.
If the owner or operator of the source wishes to increase release of a criteria
air pollutant, an offset (reduction of a somewhat greater amount of
the same pollutant) must be obtained either at the same plant or by purchasing
offsets from another company.
Oxygenated fuel (oxyfuel)
-- special type of gasoline, which burns more completely than regular gasoline
in cold start conditions; more complete burning results in reduced production
of carbon monoxide, a criteria air pollutant. In some parts of
the country, carbon monoxide release from cars starting up in cold weather
makes a major contribution to pollution. In these areas, gasoline refiners
must market oxygenated fuels, which contain a higher oxygen content than
regular gasoline. Some gasoline companies started selling oxyfuels in cities
with carbon monoxide problems before the 1990 Clean Air Act was passed.
Ozone -- a gas which is a
variety of oxygen. The oxygen gas found in the air consists of two oxygen
atoms stuck together; this is molecular oxygen. Ozone consists of three oxygen
atoms stuck together into an ozone molecule. Ozone occurs in nature; it
produces the sharp smell you notice near a lightning strike. High
concentrations of ozone gas are found in a layer of the atmosphere -- the stratosphere
-- high above the Earth. Stratospheric ozone shields the Earth against harmful
rays from the sun, particularly ultraviolet B. Smog's main
component is ozone; this ground-level ozone is a product of reactions among
chemicals produced by burning coal, gasoline and other fuels, and chemicals
found in products including solvents, paints, hairsprays, etc.
Ozone hole -- thin place
in the ozone layer located in the stratosphere high above the Earth.
Stratospheric ozone thinning has been linked to destruction of stratospheric
ozone by CFCs and related chemicals. The 1990 Clean Air Act has
provisions to reduce and eliminate ozonedestroying chemicals' production and
use. Ozone holes have been found above Antarctica and above Canada and
northern parts of the United States, as well as above northern Europe.
Particulates particulate matter
(PM-10) -- a criteria air pollutant. Particulate matter includes
dust, soot and other tiny bits of solid materials that are released into and
move around in the air. Particulates are produced by many sources, including
burning of diesel fuels by trucks and buses, incineration of garbage, mixing
and application of fertilizers and pesticides, road construction, industrial
processes such as steel making, mining operations, agricultural burning (field
and slash burning), and operation of fireplaces and woodstoves. Particulate
pollution can cause eye, nose and throat irritation and other health problems.
Permit -- a document that
resembles a license, required by the Clean Air Act for big (major)
sources of air pollution, such as power plants, chemical factories and, in
some cases, smaller polluters. Usually permits will be given out by states,
but if EPA has disapproved part or all of a state permit program, EPA will
give out the permits in that state. The 1990 Clean Air Act includes
requirements for permit applications, including provisions for members of the
public to participate in state and EPA reviews of permit applications. Permits
will have, in one place, information on all the regulated pollutants at a
source. Permits include information on which pollutants are being released,
how much the source is allowed to release, and the program that will be used
to meet pollutant release requirements. Permits are required both for the
operation of plants (operating permits) and for the construction of new
plants. The 1990 Clean Air Act introduced a nationwide permit system for air
pollution control.
Permit fees -- fees paid
by businesses required to have a permit. Permit fees are like the fees
drivers pay to register their cars. The money from permit fees will help pay
for state air pollution control activities.
Pollutants (pollution) --
unwanted chemicals or other materials found in the air. Pollutants can harm
health, the environment and property. Many air pollutants occur as gases or
vapors, but some are very tiny solid particles: dust, smoke or soot.
Primary standard -- a pollution
limit based on health effects. Primary standards are set for criteria air
pollutants.
Reformulated gasoline --
specially refined gasoline with low levels of smog-forming volatile organic
compounds (VOCs) and low levels of hazardous air pollutants. The
1990 Clean Air Act requires sale of reformulated gasoline in the nine
smoggiest areas. Reformulated gasolines were sold in several smoggy areas even
before the 1990 Clean Air Act was passed.
Secondary standard -- a pollution
limit based on environmental effects such as damage to property, plants,
visibility, etc. Secondary standards are set for criteria air pollutants.
Smog -- a mixture of pollutants,
principally ground-level ozone, produced by chemical reactions in the
air involving smog-forming chemicals. A major portion of smog-formers come
from burning of petroleum-based fuels such as gasoline. Other smog-formers, volatile
organic compounds, are found in products such as paints and solvents. Smog
can harm health, damage the environment and cause poor visibility. Major smog
occurrences are often linked to heavy motor vehicle traffic, sunshine, high
temperatures and calm winds or temperature inversion (weather condition
in which warm air is trapped close to the ground instead of rising). Smog is
often worse away from the source of the smog-forming chemicals, since the
chemical reactions that result in smog occur in the sky while the reacting
chemicals are being blown away from their sources by winds.
Source -- any place or
object from which pollutants are released. A source can be a power
plant, factory, dry cleaning business, gas station or farm. Cars, trucks and
other motor vehicles are sources, and consumer products and machines used ir
industry can be sources too. Sources that stay in one place are referred to as
stationary sources; sources that move around, such as cars or planes,
are called mobile sources.
State implementation plan
(SIP) -- a detailed description of the programs a state will use to carry
out its responsibilities under the Clean Air Act. State implementation
plans are collections of the regulations used by a state to reduce air pollution.
The Clean Air Act requires that EPA approve each state implementation plan.
Members of the public are given opportunities to participate in review and
approval of state implementation plans.
Stationary source -- a
place or object from which pollutants are released and which does not
move around. Stationary sources include power plants, gas stations,
incinerators, houses etc.
Stratosphere -- part of
the atmosphere, the gases that encircle the Earth. The stratosphere is a layer
of the atmosphere 9-31 miles above the Earth. Ozone in the stratosphere
filters out harmful sun rays, including a type of sunlight called ultraviolet
B, which has been linked to health and environmental damage.
Sulfur dioxide -- a criteria
air pollutant. Sulfur dioxide is a gas produced by burning coal, most
notably in power plants. Some industrial processes, such as production of
paper and smelting of metals, produce sulfur dioxide. Sulfur dioxide is
closely related to sulfuric acid, a strong acid. Sulfur dioxide plays an
important role in the production of acid rain.
Temperature inversion --
one of the weather conditions that are often associated with serious smog
episodes in some portions of the country . In a temperature inversion, air
doesn't rise because it is trapped near the ground by a layer of warmer air
above it. Pollutants, especially smog and smog-forming chemicals,
including volatile organic compounds, are trapped close to the ground.
As people continue driving, and sources other than motor vehicles continue to
release smog-forming pollutants into the air, the smog level keeps getting
worse.
Ultraviolet B (UVB) -- a
type of sunlight. The ozone in the stratosphere, high above the
Earth, filters out ultraviolet B rays and keeps them from reaching the Earth.
Ultraviolet B exposure has been associated with skin cancer, eye cataracts and
damage to the environment. Thinning of the ozone layer in the stratosphere
results in increased amounts of ultraviolet B reaching the Earth.
Vapor recovery nozzles --
special gas pump nozzles that will reduce release of gasoline vapor into the
air when people put gas in their cars. There are several types of vapor
recovery nozzles, so nozzles may look different at different gas stations. The
1990 Clean Air Act requires installation of vapor recovery nozzles at
gas stations in smoggy areas.
Volatile organic compounds (VOCs)
-- Organic chemicals all contain the element carbon (C); organic chemicals are
the basic chemicals found in living things and in products derived from living
things, such as coal, petroleum and refined petroleum products. Many of the
organic chemicals we use do not occur in Nature, but were synthesized by
chemists in laboratories. Volatile chemicals produce vapors
readily; at room temperature and normal atmospheric pressure, vapors escape
easily from volatile liquid chemicals. Volatile organic chemicals include
gasoline, industrial chemicals such as benzene, solvents such as toluene and
xylene, and tetrachloroethylene (perchloroethylene, the principal dry cleaning
solvent). Many volatile organic chemicals are also hazardous air pollutants;
for example, benzene causes cancer.
