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Air Quality Program

Air Quality Maps of Maintenance Areas

Areas that have experienced persistent air quality problems are designated by the U.S. Environmental Protection Agency (EPA) as nonattainment areas.  The federal Clean Air Act requires additional air pollution controls in these areas.  Each nonattainment area is declared for a specific pollutant; however, nonattainment areas for different pollutants may overlap each other or share common boundaries.

EPA had designated 13 areas in Washington State as nonattainment.  After air monitoring shows that a nonattainment area is meeting health-based air quality standards, EPA redesignated the areas as attainment.  To be redesignated, an area must both meet air quality standards, and have a 10-year plan for continuing to meet and maintain air quality standards and other requirements of the Clean Air Act.  Areas that are redesignated to attainment are called maintenance areas.

Here are the areas in Washington State designated as maintenance areas:

Ozone:  Puget Sound (King, Pierce and Snohomish Counties) and Vancouver (Clark County) are maintenance areas.

Particulate Matter (PM10): Thurston County, Tacoma Tideflats, Kent Valley, and Seattle Duwamish, Spokane, Yakima, and Wallula (Sept 26, 2005) are maintenance areas.   

Particulate Matter (PM2.5): Tacoma-Pierce County

Carbon Monoxide: Puget Sound (King, Pierce and Snohomish Counties) Yakima, Vancouver (Clark County) and Spokane are maintenance areas.


Ozone Maps

Particulate Matter Maps

Carbon Monoxide Maps

Pollutant Description Sources Health Effects
Carbon Monoxide (CO) An odorless, tasteless, colorless gas which is emitted primarily from any form of combustion. Mobile sources (autos, trucks, buses), Wood stoves, Open burning, Industrial combustion sources. Deprives the body of oxygen by reducing the blood’s capacity to carry oxygen; causes headaches, dizziness, nausea, listlessness and in high doses, may cause death.
Ozone (O3) Formed when nitrogen oxides and volatile organic compounds react with one another in the presence of sunlight and warm temperatures. A component of smog. Mobile sources, Industry, Power plants, Gasoline storage and transfer, Paint. Irritates eyes, nose, throat and respiratory system; especially bad for those with chronic heart and lung disease, as well as the very young and old, and pregnant women.
Particulate Matter

PM10 and PM2.5

Particles of soot, dust, and unburned fuel suspended in the air. Wood stoves, Industry, Dust, Construction, Street sand application, Open burning. Aggravates ailments such as bronchitis and emphysema; especially bad for those with chronic heart and lung disease, as well as the very young and old, and pregnant women.

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