Outdoor air pollution is what results when harmful chemicals, particles
and gases are discharged into the air we breathe. Most outdoor air pollution is caused by human activity.
Outdoor air pollution comes from many different sources including factories, power plants and smelters and smaller sources such as dry cleaners and degreasing operations; mobile sources such as cars, buses, planes, trucks and trains; and naturally occurring sources such as windblown dust and volcanic eruptions, all contribute to air pollution. Air quality can be affected in many ways by the pollution emitted from these sources. These pollution sources can also emit a wide variety of pollutants. Some of the most common sources are: ozone, particulate matter, carbon monoxide, nitrogen dioxide, sulphur dioxide and lead.
About ozone: Ozone is created by a chemical reaction between gases in the presence of sunlight. It occurs both in the Earth’s upper atmosphere and at ground level. Depending on its location in the atmosphere, it can be either good or bad. “Good” ozone occurs about 10–30 miles above the surface of the earth as it forms a layer offering protection from the sun’s harmful rays. However, ozone below this point is harmful to people’s general health, particularly respiratory health. This ground level ozone is a primary element of smog. Motor vehicle ex – haust and industrial emissions, gasoline vapors, chemical solvents and even some natural sources release the gases that make up ozone. Remember this about ozone: “Good up high, bad nearby!”
Breathing ground-level ozone can trigger chest pain, coughing, throat irritation, wheezing and congestion. It can worsen existing problems such as bronchitis, emphysema and asthma. It re duces lung function, inflames lining of lungs and repeated exposure can permanently scar lung tissue. Unhealthy ozone levels especially affect people with existing lung disease, children, older adults, as well as people who are active in outdoor sports and activities.