Ozone Monitoring Program

The Bureau of Air Quality operates and maintains a variety of ambient
air monitoring equipment around the state. Some of these instruments operate on
a continuous basis and provide hourly averages of pollutants or meteorological
data that is used in the evaluation of the air pollutant data. Data may also be
collected over a twenty-four hour period such as particulates or it may be
collected as a composite over an entire week. Examples of the latter are the
atmospheric and mercury deposition monitoring programs. The number of
monitoring sites and the pollutants that are monitored may vary from year to
year depending on the expected concentrations of the pollutants, the origin of
the pollutants and new programs based on changes in existing regulations or the
establishment of new regulations.

Ozone is an extremely reactive gas comprised of three atoms of oxygen. Ozone
exists naturally in the earth's upper atmosphere, the stratosphere, where it
shields the earth from the sun's harmful ultraviolet rays. However, ozone found
close to the earth's surface, called ground-level ozone, is a component of smog
and a harmful pollutant.

Sponsor: Maine Department of Environmental Protection, United States
Environmental Protection Agency, National Park Service - Air Resources Division