What is Ozone?
Ozone is an odorless, invisible atmospheric gas.
Ozone: Good up high, bad nearby
Ozone occurs naturally in the stratosphere where it forms a protective layer that shields us from harmful ultraviolet rays. This is called "good" ozone. Human activity has depleted this ozone layer and caused "holes," but due to a reduction in the use of certain chemicals, it is predicted that the ozone layer could recover. Ground-level ozone is called "bad" ozone and is the main ingredient in smog. It is also the primary pollutant of concern in southeast Florida. When emissions from motor vehicles, lawn maintenance equipment, power plants and gas stations react with the sun, they form ozone. Warm temperatures and low wind speeds during the summer months make summer the ozone season!
Ozone in the Southeast Florida Airshed
Ozone does not recognize county boundaries. Instead, it drifts within air masses throughout our region. The U.S. Environmental Protection Agency (EPA) has established a national health standard for ozone and determined that Broward, Miami-Dade and Palm Beach counties are considered the southeast Florida airshed.
In 1979, Broward County and the southeast Florida airshed encountered high ozone levels, and we were considered a non-attainment area for ozone. We exceeded the levels for ozone that were based on national health standards established by the EPA called the National Ambient Air Quality Standard (NAAQS).
In 1990 the Clean Air Act Amendments (CAA) required automobile manufacturers to produce cleaner cars that run on cleaner fuels, and implemented programs to control ozone forming emissions. An example is the vapor recovery devices at gas pumps. Due to measures such as these and local efforts, the S.E. Florida airshed was reclassified in 1995 as attainment for ozone!