Glossary of Terms

FILTER BY:
A
Abatement
The reduction in degree, intensity, or elimination of pollution.
Acid deposition
A term for the conversion of sulfur oxide and nitrogen oxide emissions into acidic compounds, which precipitate in rain, snow, fog, or dry particles.
Acute
Occurring over a short period of time; used to describe brief exposures and effects that appear promptly after exposure.
Adverse health effects
Health effects from exposure to air contaminants that may range from relatively mild temporary conditions, such as minor eye or throat irritation, shortness of breath, or headaches, to permanent and serious conditions such as birth defects, cancer, or damage to lungs, nerves, liver, heart, or other organs.
Aerosol
A particle of solid or liquid matter that can remain suspended in the air because of its small size (generally less than 1 micron).
Afterburner
An air pollution abatement device that removes undesirable organic gases through incineration.
Air
So-called "pure" air is a mixture of gases containing about 78% nitrogen; 21% oxygen; less than 1% of carbon dioxide, argon, and other inert gases; and varying amounts of water vapor.
Air basin
An area defined by geographic or administrative boundaries; used for air pollution control programs.
Air monitoring
Sampling for and measuring of pollutants present in the atmosphere.
Air pollution
The presence of polluting gases and suspended particles in the atmosphere in excess of air quality standards.
Air quality criteria
The varying amounts of pollution and lengths of exposure at which specific adverse effects to health and comfort take place.
Air Quality Management District (AQMD)
Local agency charged with controlling air pollution and attaining air quality standards. The Air District is the regional AQMD that includes all of seven counties (Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo and Santa Clara) and the southern halves of Solano and Sonoma counties.
Air quality plan (AQP)
A plan developed to attain and maintain an air quality standard.
Air Quality Standard (AQS)
The prescribed level of a pollutant in the outside air that should not be exceeded during a specific time period to protect public health. Established by both federal and state governments.
Airshed
A term denoting a geographical area that, because of topography, meteorology, and climate, shares the same air (see Air Basins).
Ambient air
Outside air; any portion of the atmosphere not confined by walls and a roof.
Aromatic
A hydrocarbon that consists of 1 or more benzenoid rings (i.e., benzene).
Asbestos
A mineral fiber that can pollute air or water and cause cancer or asbestosis when inhaled. EPA has banned or severely restricted its use in manufacturing and construction.
Association of Bay Area Governments (ABAG)
A voluntary joint-power comprehensive regional planning agency for the cities and counties of the Bay Area.
Asthma
A medical condition characterized by abnormal restriction of breathing, especially in response to allergens or air contaminants.
Atmosphere
The layer of life-supporting gases (air) that surrounds the earth.
Attainment
A designation used when an area meets an air quality standard.
Attrition fire
A fire whose fuel is comprised of dead or pruned tree or bush branches, limbs, and cuttings.
Authority to Construct (A/C)
A pre-construction permit issued by the Air District.

Contact Us

Communications
General Information

415.749.4900

Meteorology & Measurements
Air Monitoring

415.749.4985

Contact Us

Spare the Air Status

Last Updated: 6/12/2023