What is Air Pollution?

There are many kinds of air pollution. The Environmental Protection Agency (EPA) calculates the Air Quality Index (AQI) for five major air pollutants regulated by the Clean Air Act: ground-level ozone, particle pollution, carbon monoxide, sulfur dioxide, and nitrogen dioxide. Ozone and particle pollution are two common pollutants found in many parts of the country.

  • Ozone is a colorless odorless gas. It’s the same kind of gas that’s found in the ozone layer. But in the ozone layer – high in the Earth’s stratosphere – ozone protects us from the sun. At ground level, where we live, ozone pollution is unhealthy to breathe. Ground-level ozone forms when pollutants from cars, trucks, power plants, industries, and some consumer products “cook” in the sun. Ozone usually peaks during the afternoon hours, when sunlight is the most intense.More about ozone.
  • Particle pollution, also called particulate matter, consists of microscopic particles in the air. It can be a problem in the winter or summer, depending on where you live. Particle pollution causes haze, blurring the view in many cities and national parks. And like ozone, it’s not healthy to breathe. More about particle pollution. Particulate matter is also found in smoke. More about how smoke from fires can affect your health.

More about the six common air pollutants