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Current Air Quality

Air Quality Index

Local air quality affects how you live and breathe. Like the weather, it can change from day to day or even hour to hour. The U.S. Environmental Protection Agency (EPA) and others are working to make information about outdoor air quality as easy to understand as the weather forecast. A key tool in this effort is the Air Quality Index, or AQI.

Air Quality Where You Live

EPA uses six "criteria pollutants" as indicators of air quality, and has established for each of them a maximum concentration above which adverse effects on human health may occur. These threshold concentrations are called National Ambient Air Quality Standards (NAAQS).

When an area does not meet the air quality standard for one of the criteria pollutants, it may be subject to the formal rule-making process which designates it as nonattainment. The Clean Air Act further classifies ozone, carbon monoxide, and some particulate matter nonattainment areas based on the magnitude of an area's problem. Nonattainment classifications may be used to specify what air pollution reduction measures an area must adopt, and when the area must reach attainment. The technical details underlying these classifications are discussed in the Code of Federal Regulations, Part 81 (40 CFR 81).

You may be wondering: How does the air quality in my city compare with other cities? What time of year has the best air quality? Has the air quality in my city improved? AirCompare provides local air quality information to help you make informed, health-protective decisions about moving or vacationing.

Air Quality Monitoring

One way to protect and assess air quality is through the development of an ambient air monitoring program. Air quality samples are generally collected for one or more of the following purposes:


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