Glossary of Terms
- Air
Pollution
- The contamination of the atmosphere by
waste gases, fuel exhaust, particulate matter such as smoke, and the
like.
- Air
Quality Monitoring
- Periodic or continuous surveillance or
testing to measure polluntants in the air.
- Ambient
Air
- That portion of the atmosphere, external
to buildings, to which the general public has access.
- Attainment
Area
- A region or area that meets the National
Ambient Air Quality Standards (NAAQS) set by EPA.
- Carbon
Dioxide (CO2)
- A colorless, odorless gas that consists
of one atom of carbon and two atoms of oxygen. It is the product of
a chemical reaction between carbon-based materials and oxygen
- Carbon
Monoxide (CO)
- A colorless, odorless, poisonous gas,
produced by incomplete burning of carbon-based fuels, including gasoline,
oil and wood. 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.
- Chlorofluorocarbons
(CFCs)
- Any of various gaseous compounds of carbon,
hydrogen, chlorine, and fluorine. These chemicals and some related chemicals
have been used in great quantities in industry, for refrigeration and
air conditioning, and in consumer products. When CFCs and their relatives
are released into the air, they rise into the stratosphere. In the stratosphere,
CFCs take part in chemical reactions which result in reduction of the
stratospheric ozone layer (good ozone), the layer which protects the
Earth’s surface from harmful effects of radiation from the sun
- Clean
Air Act
- The legislation, originally enacted in
1963, revised in 1970 and 1977, and amended in 1990, which is the basis
for the national air pollution control program.
- Climate
- The characteristic meteorological conditions,
such as temperature, precipitation, and wind, that prevail in a particular
area or region over a period of time.
- Climatology
- The science of how the Earth’s temperature
and weather patterns are created and changed.
- Combustion
- Burning, or rapid oxidation, accompanied
by a release of energy in the form of heat and light. A basic cause
of air pollution.
- Concentration
- The amount of a substance contained in
a specific quantity of another solution or a mixture.
- Contaminant
- Any physical, chemical, biological, or
radiological substance or matter that has an adverse affect on air,
water, or soil.
- Convection
- A meteorological term meaning a rapid
upward movement of air that occurs through the strong heating of the
Earth’s surface and supportive atmosphere instability. Winds and
currents are mainly driven by convection in the atmosphere and in the
oceans
- Criteria
(air) Pollutant
- One of a group of 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.
- Emissions
- Pollution discharged into the atmosphere
from a source such as smokestacks, vents, and other areas of commercial
or industrial facilities; from residential activities; and from motor
vehicle, locomotive, and aircraft exhaust.
- Emission
Standard
- A numerical quantity that defines the
allowable rate at which a contaminant may be discharged.
- Extrapolation
- A scientific method of applying or transferring
experimental observations from a model to the real world. Extrapolation
is frequently necessary because effects in the real world are usually
too slow or too minute to measure.
- Hydrocarbons
- Chemical compounds that consist entirely
of carbon and hydrogen. Hydrocarbons are a major contributor to ozone.
- Hypothesis
- A supposition, hunch or guess about what
or why something happens. More specifically, a proposition put forth
as a basis for reasoning; a supposition formulated from proved data
and presented as a temporary explanation of an occurrence, as in the
sciences, often to establish as basis for further research.
Lead
- A heavy metal that may be
hazardous to health if breathed or swallowed
 (for example, by a child eating soil or
paint contaminated with lead). Lead occurs in the atmosphere
as particulate matter originating from natural and artificial
pollution sources.
- Mitigation
- The reduction of impacts
caused by pollution. Mitigation can include preventing
the pollution, cleaning up the pollution, or reducing
the pollution. Mitigation can be accomplished through
engineering solutions (such as air pollution “scrubbers”
on power plants) or process solutions (such as recycling).
- Mobile
Source Emissions
- The release of pollutants
into the air from motor vehicles
- Monitoring
- Periodic or continuous surveillance
or testing to collect specific types of data. Air is monitored
to measure air pollution. See Air Quality Monitoring.
- National
Ambient Air Quality Standards (NAAQS)
- Levels of pollutants that
cannot be exceeded. These levels are prescribed by law
or regulation for outside air.
- Nitrogen
Dioxide (NO2)
- The result of nitric oxide
combing with oxygen in the atmosphere. It is a major component
of ozone.
- Nitrogen
Oxides (NOx)
- Gases formed in great part
from atmospheric nitrogen and oxygen when combustion takes
place under conditions of high temperature and pressure.
Nitrogen oxides include nitric oxide (NO) and nitrogen
dioxide (NO2).
- Nonattainment
Area
- A region or area that fails
to meet the National Ambient Air Quality Standards (NAAQS)
set by EPA.
- Ozone
(O3)
- A principal component of
smog. Ozone can be either good or bad for living things,
depending upon where it is. Ground-level ozone or “bad”
ozone is harmful and can cause adverse health effects,
and is known to harm trees and plants. However, an ozone
layer (“good” ozone) that exists naturally in
the stratosphere keeps out most of the dangerous ultraviolet
rays from the sun that can cause skin cancer
- Particulate
Matter
- Very small particles, such
as dust of fiber. The major source of atmospheric particulates
includes combustion of coal, gasoline, and fuel oil; cement
production; lime kiln operation; incineration; and agricultural
burning.
- Photochemical
Reaction
- A chemical reaction in the
atmosphere that is triggered by sunlight. Ozone is a pollutant
created from a photochemical reaction.
- Point
Source
- A discrete stationary source
of pollution, such as a smoke stack.
- Policy
- Any plan or course of action
adopted by a government, business organization, or the
like, designed to influence and determine decisions and
actions. For example, Clean Air regulations constitute
policy issued by the EPA to control air pollution.
- Pollutant
- Any substance introduced
into the environment that adversely affects the usefulness
of a resource. Air pollutants are unwanted chemicals or
other materials found in the air, such as gases, vapors,
dust, smoke, or soot.
- Pollution
- An adverse impact upon the
natural environment. For example, air pollution can come
from the stacks of power plants when they burn oil or
coal to produce electricity or from the operation of automobiles
- Prediction
- A projection in advance
of an event based on observation, experience, or scientific
reason.
- Respiration
- The physical and chemical
processes by which an organism supplies its cells and
tissues with the oxygen needed for metabolism and relieves
them of the carbon dioxide formed in energy producing
reactions.
- Scientific
Method
- An iterative process in
which a hypothesis is tested through experiments and compared
to observation.
- Smog
- A mixture of pollutants,
principally ground-level ozone (“bad” ozone),
produced by chemical reactions in the air. Smog can harm
health, damage the environment, and cause poor visibility.
- Stratospheric
Ozone (Good Ozone)
- Ozone located in the portion
of the atmosphere that is a few miles above the Earth’s
surface. Ozone at this altitude filters out harmful sun
rays, including those that may cause health and environmental
damage.
- Sulfur
Dioxide (SO2)
- A colorless, irritating
gas formed by the burning of sulfur-containing material.
Sulfur dioxide can react with other atmospheric chemicals
to form sulfuric acid.
- Thermal
Inversion
- A layer of warm air settling
over a layer of cool air that lies near the ground. This
condition prevents air pollution from rising and dissipating.
- Tropospheric
Ozone (Bad Ozone)
- Ground-level ozone (“bad”
ozone), produced by chemical reactions in the air. Ozone
can harm health, damage the environment, and cause poor
visibility.
- Volatile
Organic Compounds (VOCs)
- Organic compounds, such
as gasoline, industrial chemicals, and solvents that participate
in atmospheric photochemical reactions.
- Weather
- Meteorological term meaning
the condition of the atmosphere at a particular time or
area with respect to temperature, moisture, cloud cover,
and wind velocity.
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