Air Quality and Health

The term “air pollution” refers to chemicals or particles in the air that can cause harm to humans or other living organisms and damage the natural environment. In the San Antonio region, ground-level ozone is our primary kind of air pollution.

Ozone is a gas that occurs both in the Earth's upper atmosphere and at ground level. Ozone can be "good" or "bad" depending on its location. In an upper layer of the atmosphere called the stratosphere, the “ozone layer” is good because it blocks harmful ultraviolet rays. Near the ground, in the air we breathe, ozone is bad because it hurts our lungs and harms other living things.

Ground-level ozone pollution is formed when Nitrogen Oxides (which are found in emissions from vehicles, refineries, and manufacturing or power plants) and Volatile Organic Compounds (which found in gasoline, paint, and cleaning fluids), combine together on hot, sunny days. Because ozone forms during sunny and hot conditions, it is most likely to be a problem during San Antonio’s long, hot summers. Our “ozone season” lasts from March 1 through November 30.

People who are young, who already have breathing problems, or who exercise or work outdoors are harmed the most by ground-level ozone pollution. Symptoms of ozone exposure include coughing, wheezing, pain when taking a deep breath, and breathing difficulties during exercise or outdoor activities. In addition to the respiratory symptoms mentioned above, ozone can inflame airways, aggravate asthma or other respiratory diseases, and increase one’s susceptibility to respiratory infection. Long-term exposure can also accelerate aging of the lungs, diminish lung capacity, and decrease lung function.

When scientists think there will be an unhealthy level of ozone the next day, the government sends out an alert for an Ozone Action Day. On an Ozone Action Day, it is not a good idea to be outside for long periods of time, especially if you are in a more susceptible category. If you would like to receive an email warning of an Ozone Action Day, please contact Lyle Hufstetler at AACOG. 

For more information, visit the U.S. Environmental Protection Agency's Air Now Website.