Air Quality

What is particulate matter, and what causes it?

Particulate matter is the term for particles found in the air including dust, dirt, smoke, soot and liquid droplets. Particles can be suspended in the air for long periods of time. Some particles are large or dark enough to be seen as dust or smoke. Others are so small that they can be seen only with an electron microscope. Some particles are directly emitted into the air. They come from a variety of sources such as smoking vehicles, construction sites, tilled fields, unpaved roads, stone crushing, and open burning. Other particles are formed in the air from chemical reactions of gases in the presence of sunlight and water vapor. They result from emissions of sulfur dioxide, nitrogen oxides, ammonia, and volatile organic compounds-gases emitted by cars, power plants, industrial plants, gasoline dispensing facilities, painting operations, and natural sources.

What is ozone, and what causes it?

Ozone is a gas composed of three atoms of oxygen. Ozone occurs both in the Earth’s upper atmosphere and at ground level. Ozone can be good or bad, depending on where it is found.

Good Ozone: Ozone occurs naturally in the upper atmosphere (6 to 30 miles above the ground) where it forms a protective layer that shields us from the sun’s harmful ultraviolet rays.

Bad Ozone: In the Earth’s lower atmosphere, near ground level, ozone is a harmful air pollutant also known as “smog.” Ground-level ozone is formed when nitrogen oxides and volatile organic compounds (gases emitted by cars, power plants, industrial plants, gasoline dispensing facilities, painting operations, and natural sources) react chemically in the presence of sunlight. Ground-level ozone builds up during the day, especially during warm weather, and drops off at night.

While Florida meets the national air quality standard for ozone, all areas of the state experience a few days each year when ozone levels are high enough to affect sensitive persons. On such days, the Air Quality Index may reach the “yellow” or “orange” range and some people may experience coughing, throat irritation, and breathing discomfort. Look for the Air Quality Index report in your local media or view the AQI report online on our Ozone Forecast and Air Quality Index page.

What is smoke pollution?

On average, Florida experiences the second highest number of wildfires in the nation. During dry years, Florida experiences severe wildfires—wildfires that destroy homes, disrupt people’s lives and impact our economy. For more information on smoke pollution and the effects it can have on your health, view: