Terms You Should Know About Pollution

Pollution streets

Acid Rain:

Air pollution produced when acid chemicals are incorporated into rain, snow, fog or mist. The "acid" comes from sulfur oxides and nitrogen oxides, products of burning coal and other fuels. 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.

Air Quality Index:

The standard system that state and local air pollution control programs use to notify the public about levels of air pollution. The AQI tracks levels of two pollutants - ozone (smog) and particle pollution (tiny particles from ash, vehicle exhaust, soil dust, pollen, and other pollution).

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.

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, including cigarette smoke. When carbon monoxide enters the body, it reacts with chemicals in the blood and prevents the blood from bringing oxygen to cells, tissues, and organs. The body needs oxygen for energy, so high-level exposures to carbon monoxide can cause serious health effects and even death. Symptoms of exposure to carbon monoxide can include vision problems, reduced alertness, and general reduction in mental and physical functions.

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. When CFCs are released into the air, they rise into the stratosphere, a layer of the atmosphere high above the Earth, where they take part in chemical reactions which result in reduction of the stratospheric ozone layer.

Clean Air Act (CAA):

The original Clean Air Act was passed in 1963, but our national air pollution control program is actually based on the 1970 update. The 1990 Clean Air Act Amendments are the most far-reaching revisions of the 1970 law, which is also 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).


Another word for 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.


Release of pollutants into the air from a source.

Hazardous Air Pollutants (HAPs):

Toxic chemicals that cause serious health and environmental effects. Health effects include cancer, birth defects, nervous system problems, and death due to massive accidental releases. Hazardous air pollutants are released by sources such as chemical plants, dry cleaners, printing plants, and motor vehicles.

Mobile Sources:

Motor vehicles and other moving objects that release pollution. 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.


National ambient air quality standards. Ambient standards developed by EPA that must be attained and maintained to protect public health. NAAQS exist for specific matter, sulfur dioxide, nitrogen dioxide, ozone, carbon dioxide, and lead.

Nitrogen Oxides (NOx):

Nitrogen oxides are produced from burning fuels, including gasoline and coal. They react with volatile organic compounds to form smog, and become air pollutants included in acid rain.


A gas which is a variety of oxygen. 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. It is also the main component of smog.

Particulates/Particulate Matter:

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 wood stoves. Particulate pollution can cause eye, nose, and throat irritation and other health problems.

Pollutants (pollution):

Unwanted chemicals or other materials found in the air, water, and/or ground. 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.


A mixture of pollutants, principally ground-level ozone, produced by chemical reactions in the air. A major portion of smog-formers comes from burning petroleum-based fuels such as gasoline, but also include volatile organic compounds that are found in products such as paints and solvents. Smog can harm health, damage the environment and cause poor visibility.


Any place or object from which pollutants are released. A source can be a power plant, factory, dry cleaning business, gas station, or a farm. Cars, trucks, and other motor vehicles are sources. Consumer products and machines used in industry can also be sources.

Stationary Source:

A place or object from which pollutants are released which does not move. Stationary sources include power plants, gas stations, incinerators, and houses.

Sulfur Dioxide:

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, and also 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.

Ultraviolet B (UVB):

A type of sunlight. The ozone in the stratosphere filters out ultraviolet B rays and keeps them from reaching the Earth. Thinning of the ozone layer in the stratosphere results in increased amounts of ultraviolet B reaching the Earth. Ultraviolet B exposure has been associated with skin cancer, eye cataracts, and damage to the environment.

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 readily produce vapors at room temperature and normal atmospheric pressure. Vapors escape easily from volatile liquid chemicals. Volatile organic chemicals include gasoline, industrial chemicals.


Environmental Protection Agency
Health Goods
Nova Science in the News