| 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). |
