What is an air quality forecast?
An air quality forecast is much like a weather forecast-it
predicts the air quality for the next day. The weather plays an
important role in air quality. Hot, dry, stagnant weather allows
pollutants to accumulate in an area. For example, ozone pollution
is formed when certain air pollutants (oxides
of nitrogen and volatile organic compounds) mix and react in
hot, sunny weather. When the air is stagnant, pollutants may be
suspended in the air over extended periods.
How does the air quality forecast work?
The Tennessee Department of Environment and Conservation
(TDEC) issues forecasts in cooperation with the Tennessee Valley
Authority and local air quality control programs. Daily air quality
forecasts are issued for urban centers of the state, including Tri-Cities,
Chattanooga, Knoxville, Nashville and Memphis. Forecasts are reported
using the
Air Quality Index or AQI, which uses a color-coded system to
help you understand quickly if the air quality is expected to be
healthy or unhealthy in your community. The U.S. Environmental Protection
Agency (EPA) developed this national rating scale based on federal
air quality health standards. EPA has assigned a specific
color to each AQI category (click to view table).
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