Stratospheric ozone is “good” because it protects living things from ultraviolet radiation from the sun. Ground-level ozone, the topic of this website, is “bad” because it can trigger a variety of health problems, particularly for children, the elderly, and people of all ages who have lung diseases such as asthma.

What is the bad ozone layer?

Ozone occurs in two layers of the atmosphere. The layer closest to the Earth's surface is the troposphere. Here, ground- level or “bad” ozone is an air pollutant that is harmful to breathe and it damages crops, trees and other vegetation. It is a main ingredient of urban smog.

Why Ground level ozone is bad?

Breathing ground-level ozone can trigger a variety of health problems including chest pain, coughing, throat irritation, and congestion. It can worsen bronchitis, emphysema, and asthma. Ozone also can reduce lung function and inflame the lining of the lungs. Repeated exposure may permanently scar lung tissue.