APES Chapter 15 - Atmospheric Pollution and Stratospheric Ozone Depletion

Air pollution

The introduction of chemicals, particulate matter, or microorganisms into the atmosphere at concentrations high enough to harm plants, animals, and materials such as buildings, or to alter ecosystems.

Particulate matter (PM)

Solid or liquid particles suspended in air. (Also known as "particulates"; "particles.")

Particulates

See "particulate matter."

Particles

See "particulate matter."

Haze

Reduced visibility.

Photochemical oxidant

A class of air pollutants formed as a result of sunlight acting on compounds such as nitrogen oxides.

Ozone (O3)

A secondary pollutant made up of three oxygen atoms bound together.

Smog

A type of air pollution that is a mixture of oxidants and particulate matter.

Photochemical smog

Smog that is dominated by oxidants such as ozone. (Also known as "Los Angeles–type smog"; "brown smog.")

Los Angeles–type smog

See "photochemical smog."

Brown smog

See "photochemical smog."

Sulfurous smog

Smog dominated by sulfur dioxide and sulfate compounds. (Also known as "London-type smog"; "gray smog"; "industrial smog.")

London-type smog

See "sulfurous smog."

Gray smog

See "sulfurous smog."

Industrial smog

See "sulfurous smog."

Volatile organic compound (VOC)

An organic compound that evaporates at typical atmospheric temperatures.

Primary pollutant

A polluting compound that comes directly out of a smokestack, exhaust pipe, or natural emission source.

Secondary pollutant

A primary pollutant that has undergone transformation in the presence of sunlight, water, oxygen, or other compounds.

Thermal inversion

A situation in which a relatively warm layer of air at mid-altitude covers a layer of cold, dense air below.

Inversion layer

The layer of warm air that traps emissions in a thermal inversion.

Asbestos

A long, thin, fibrous silicate mineral with insulating properties, which can cause cancer when inhaled.

Sick building syndrome

A buildup of toxic pollutants in an airtight space, seen in newer buildings.