Glossary
S
Any stationary container, reservoir, or tank, used for storage of liquids.
The layer of the Earth's atmosphere above the troposphere and below the mesosphere. It extends between 10 and 30 miles above the Earth's surface and contains the ozone layer in its lower portion. The stratospheric layer mixes relatively slowly; pollutants that enter it may remain for long periods of time.
A model rule developed by air quality managers for local air districts to use to control the emissions from certain stationary sources of air pollution.
(See Sulfur Oxides.)
A strong smelling, colorless gas that is formed by the combustion of fossil fuels. Power plants, which may use coal or oil high in sulfur content, can be major sources of SO2 and other sulfur oxides contribute to the problem of acid deposition. SO2 is a criteria air pollutant.
SF6 is a colorless, non-toxic and non-flammable gas under standard conditions. It is used in many applications including as a gaseous dielectric medium in the electrical industry, an inert gas for the casting of magnesium, a tracer gas and an etchant in the semiconductor industry. SF6 is the most potent greenhouse gas with a global warming potential of 23,900 times that of carbon dioxide when compared over a 100-year period.
Pungent, colorless gases (sulfates are solids) formed primarily by the combustion of sulfur-containing fossil fuels, especially coal and oil. Considered major air pollutants, sulfur oxides may impact human health and damage vegetation.
A vehicle that meets the ARB's super ultra-low emission vehicle standard of 0.03 grams per mile of NMOG+ NOx. See our Drive Clean website.
T
An intermediate gasoline distribution facility where delivery of gasoline to and from the facility is solely by pipeline.
A process in which metallic or nonmetallic materials are heated to a molten or nearly molten state and are sprayed onto a surface to form a coating. The material may originate in the form of powder, rod, or wire before it is heated, prior to spraying and deposition. Materials can be heated by combustion of fuel gases (similar to welding) or by using electricity. Thermal spraying includes processes such as flame spraying, plasma spraying, high velocity oxyfuel (HVOF) spraying and twin wire electric arc spraying.
The outermost layer of the Earth's atmosphere extending from about 60 miles to several hundred miles above the planet's surface. The temperature of this layer varies from many hundreds to thousands of degrees Celsius.
A section of the 1990 amendments to the federal Clean Air Act that addresses the control of toxic air emissions. For more information, visit our Title III website.
A section of the 1990 amendments to the federal Clean Air Act that requires a federally enforceable operating permit for major sources of air pollution. For more information, visit our Title V website.
The configuration of a surface, especially the Earth's surface, including its relief and the position of its natural and man-made features.
Gaseous organic compounds, including reactive organic gases and the relatively unreactive organic gases such as methane.
Particles of solid or liquid matter -- such as soot, dust, aerosols, fumes and mist -- up to approximately 30 microns in size.
An air pollutant, identified in regulation by the ARB, which may cause or contribute to an increase in deaths or in serious illness, or which may pose a present or potential hazard to human health. TACs are considered under a different regulatory process (California Health and Safety Code section 39650 et seq.) than pollutants subject to CAAQSs. Health effects to TACs may occur at extremely low levels and it is typically difficult to identify levels of exposure which do not produce adverse health effects. For more information, visit our toxics website.
The most effective emission limitation or control technique which has been achieved in practice or found by the ARB Executive Officer or Air Pollution Control Officer of the local districts to be technologically feasible.