Chapter 10: Air Pollution

U.S. Clean Air Act of 1963

The first national legislation in the United States aimed at air quality.

conventional or criteria pollutants

The seven substances (sulfur dioxide, carbon monoxide, particulates, hydrocarbons, nitrogen oxides, photochemical oxidants, and lead) identified by the Clean Air Act as the most serious threat of all pollutants to human health and welfare.

ambient air

The air immediately around us.

point sources

Specific locations of highly concentrated pollution discharge, such as factories, power plants, sewage treatment plants, underground coal mines, and oil wells.

nonpoint-source or fugitive emissions

Scattered, diffuse sources of pollutants, such as runoff from farm fields, golf courses, and construction sites.

primary pollutants

Chemicals released directly into the air in a harmful form.

secondary pollutants

Chemicals modified to a hazardous form after entering the air or that are formed by chemical reactions as components of the air mix and interact.

photochemical oxidants

Products of secondary atmospheric reactions.

Sulfur dioxide (SO2)

A colorless, corrosive gas directly damaging to both plants and animals.

Nitrogen oxides (NOx)

Highly reactive gases formed when nitrogen in fuel or combustion air is heated to over 650 degrees C (1,200 degrees F) in the presence of oxygen or when bacteria in soil or water oxidize nitrogen-containing compounds.

Carbon monoxide (CO)

Colorless, odorless, nonirritating but highly toxic gas produced by incomplete combustion of fuel, incineration of biomass or solid waste, or partially anaerobic decomposition of organic material.

Ozone

A highly reactive molecule containing three oxygen atoms; a dangerous pollutant in ambient air. In the stratosphere, however, ozone forms an ultraviolet absorbing shield that protects us from mutagenic radiation.

Volatile Organic Compounds (VOCs)

Organic chemicals that evaporate readily and exist as gases in the air.

Lead

The most abundantly produced metal air pollutant which impairs nerve and brain functions.

Particulate material

Atmospheric aerosols, such as dust, ash, soot, lint, smoke, pollen, spores, algal cells, and other suspended materials; originally applied only to solid particles buy now extended to droplets of liquid.

Aerosols

Minute particles and liquid droplets suspended in the air.

Hazardous Air Pollutants (HAPs)

A special category of toxins that cause cancer, nerve damage, disrupt hormone function, and fetal development. These persistent substances remain in ecosystems for long periods of time, and accumulate in animal and human tissues.

Toxic Release Inventory (TRI)

A program created by the Superfund Amendments and Reauthorization Act of 1984 that requires manufacturing facilities and waste handling and disposal sites to report annually on releases of more than 300 toxic materials. You can find out from the EPA whether any of these sites are in your neighborhood and what toxins they release.

Mercury

A heavy, silvery metallic element that is liquid at room temperature; it is a widespread and persistent neurotoxin.

Montreal Protocol

An international treaty to eliminate chloroflurocarbons that destroy stratospheric ozone.

Particulate removal

Involves filtering air emissions.

catalytic converter

The device on an automobile that uses platinum-palladium and rhodium catalysts to remove NOx, hydrocarbons, and carbon monoxide from the exhaust.

cap-and-trade agreement

A policy to set pollution limits, then allow companies to buy and sell their allotted rights to emit pollutants.