Ozone at ground level, however, is highly corrosive, damaging plant, animal, and human tissue, and other materials such as metals and masonry. It is the major component of urban smog. A. Ozone is a severe irritant. It is responsible for the choking, coughing, and stinging eyes associated with smog. Ozone damages lung tissue, aggravates respiratory disease, and makes people more susceptible to respiratory infections.
Children are especially vulnerable to ozone's harmful effects, as are adults with existing disease.
But even otherwise healthy individuals may experience impaired health from breathing ozone-polluted air. Elevated ozone levels also inhibit plant growth and can cause widespread damage to crops and forests. The standard is based on the highest ozone exposure sensitive persons can tolerate. The rate at which these reactions occur is affected by both temperature and intesity of the sunlight. For this reason, high ozone levels occur most often on hot summer afternoons.