When people think about ground-level ozone, they usually picture a thick layer of smog over Los Angeles. They don't usually think of a midwest summer day-hazy blue sky, sunny, and hot. Although ozone cannot be seen or tasted, it can irritate lungs and make breathing difficult. The urban haze that we call smog contains pollutants that react to form ozone. Most of the pollutants that form ozone come from cars.
Large factories account for another portion of the emissions.
Small Businesses such as printing plants, service stations, and auto body shops, and people using lawnmowers, paints and cleaning solvents account for another portion of the emissions. There is an association between ozone levels in the outdoor air and increased hospital admissions for respiratory causes, such as asthma. Children with respiratory problems are at greatest risk because of greater exposure to outdoors during the summer months. Asthmatics and other sensitive individuals should not exercise and should stay indoors in an air conditioned or well ventilated area. If you experience symptoms such as tightness in the chest, coughing, or wheezing, see your doctor immediately.