Arizona Department of Environmental Quality. State agency charged with protecting the Arizona environment.

Area A

"Area A" (A.R.S. Sec. 49-541) as used in this rule for Pinal County, is the area delineated on the 1994 Supervisor District Map of Pinal County as follows:
Township 1 north, range 8 east, and range 9 east; Township 1 south, range 8 east and range 9 east;
Township 2 south, range 8 east and range 9 east; Township 3 south, range 7 east through range 9 east.


Best Available Control Technology. An emissions limitation, based on the maximum degree of air pollution reduction, that is achievable through certain production methods, after taking into account energy, economic, and environmental impacts and other costs.


Best Management Practice. Methods determined to be the most effective, practical means of preventing or reducing pollution.

Clean Air Act

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

Criteria Pollutants

A group of very common air pollutants regulated by EPA on the basis of criteria (information on health and/or environmental effects of pollution). Criteria air pollutants are widely distributed all over the country. See Also:Criteria Pollutants


Environmental Protection Agency. Federal agency charged with protecting the environment.


Hazardous Air Pollutants. Chemicals that cause serious health and environmental effects. Health effects include cancer, birth defects, nervous system problems and death. Hazardous air pollutants are released by sources such as chemical plants, dry cleaners, printing plants, and motor vehicles (cars, trucks buses, etc.)

High Pollution Advisory Day

A High Pollution Advisory Day may be called by the Arizona Department of Environmental Quality when criteria air pollutant levels are forecast to reach unhealthy levels. These notices, often in partnership with local businesses, encourage Valley and Area A residents to reduce emissions of pollutants that contribute to the unhealthy levels of air pollution.
Additionally, Pinal County Air Quality forecasts the air pollution levels in Pinal County and from time to time when conditions warrant, may issue a High Pollution Advisory (HPA).


During the winter, a layer of cooler air is trapped by a layer of warmer air above, forming a temperature inversion. An inversion is an atmospheric condition caused by increasing temperature with elevation, resulting in a layer of warm air preventing the rise of cooler air trapped beneath. An inversion traps pollutants from vehicles, fireplaces, and other sources close to the ground, thus increasing the chances for carbon monoxide and particulates to reach unhealthy levels.


Maximum Available Control Technology. The emission standard requiring the maximum reduction of hazardous emissions while taking cost and feasibility into account.

Mobile Source

Moving objects that release pollution; mobile sources include cars, trucks, buses, planes, trains, motorcycles and gasoline-powered lawn mowers. Mobile sources are divided into two groups: road vehicles, which include cars, trucks and buses, and non-road vehicles, which include trains, planes and lawn mowers.


National Ambient Air Quality Standards promulgated by the EPA for the Criteria Air Pollutants.


National Emission Standards for Hazardous Air Pollutants. Emissions standards set by EPA to control certain air pollutants.

No Burn Day

No burning may be conducted in Area A when monitoring or weather forecasting indicates the carbon monoxide or particulate matter standard is likely to be exceeded in Area A.


A geographic area in which the level of a criteria air pollutant is higher than the level allowed by the federal standards.

Nonroad Source

Also referred to as "off-road" or "off-highway," the nonroad category includes outdoor power equipment, recreational vehicles, farm and construction equipment, boats, and locomotives.

Onroad Source

All vehicles that are driven on the roadway.


Ground level ozone is a colorless gas produced when sunlight and heat stimulate reactions between volatile organic compounds and nitrogen oxides. Elevated levels are generally recorded during the summer months and can aggravate respiratory problems, especially in sensitive groups.

Particulate Matter 10 (PM10)

Particulate Matter 10 (PM10) is dispersed airborne particles smaller than 10 microns (1 micron = 10-4 centimeters) that results from vehicles traveling on unpaved roads, material handling and wind blown dust. Particles this small can be deposited deep into the respiratory system and increase respiratory distress.

Particulate Matter 2.5 (PM2.5)

Particulate Matter 2.5 (PM2.5) is dispersed airborne fine particulate matter smaller than 2.5 microns (1 micron = 10-4 centimeters) that results from the combustion of fuels in motor vehicles, power generation, and industrial facilities, as well as from residential fireplaces and wood stoves. Particles this small can be deposited deep into the respiratory system and elevated levels may aggravate respiratory and cardiopulmonary problems.


Pinal County Air Quality Control District. County agency charged with protecting Pinal’s air quality environment.

Point Source

Any stationary source for which individual records are collected and maintained. A facility that releases more than a specified amount of a pollutant.


Generally, any substance introduced into the environment that adversely affects the usefulness of a resource.


Reasonably Available Control Technology. Control technology that is reasonably available and both technologically and economically feasible.


State Implementation Plan. A detailed description of the programs a state will use to carry out its responsibilities under the Clean Air Act. A SIP is a collection of the regulations used by a state to reduce air pollution. The EPA must approve each SIP and the public is given opportunities to participate in the review and approval.

Stationary Source

A source that remains at a fixed location while emitting pollutants. Any non-mobile source of pollutants.

Synthetic Minor 80% (SM80)

Facilities that are operating between 80% and 99% of the applicable major source threshold. A SM80 permit imposes federally enforceable limits to restrict a facility's potential emissions to below major source thresholds.

Title V

One of several programs authorized in the 1990 Amendments to the federal Clean Air Act (CAA). The program requires air quality agencies to issue Title V permits to major stationary sources of air pollutants.