When fossil fuels, such as gasoline are burned, a variety of pollutants are emitted into theearth's troposphere. Hydrocarbons and nitric oxide are two pollutantsthat are emitted into the air. When these pollutants build up to high levels, a chain reaction occurs from their interaction with sunlight which the nitric oxide is converted to nitrogen dioxide. Nitrogen Dioxide is a brown gas and at high levels can contribute to urban haze. A problem to be even more concerned with is that nitrogen dioxide absorbs sunlight and break up to produce oxygen atoms that combine with the oxygen in the air to produce ozone.
Ozone is a toxic gas and a very powerful oxidizing agent.
When ozone is present in the air we breathe, it is a gaseous pollutantand it is harmful to human health. Ozone creates changes inlung function and has proven to develop chronic lung diseases. Residents of communities with high ozone concentrations tend to havemore problems with their lungs. A leading cause to tropospheric ozone is air pollution. Air pollutionis not anything new to our atmosphere.