The extra atom makes the ozone molecule highly unstable and reactive. This reactivity is a problem because it breaks down substances - not only materials, but biological tissues and cells as well. Ground level ozone is harmful to human health. Sensitivity to ozone's effects is greater in some people, especially children, elderly people and people with lung or heart ailments. Even healthy people exercising outdoors may experience pulmonary discomfort when ozone concentrations reach the national standard of 0.12 parts per million.
Ozone affects more than human health.
It damages trees and plants. It also accelerates the aging of rubber, fabrics, painted surfaces and other materials. Because ground-level ozone is weather dependent, the extent of the ozone problem in Michigan can vary from year to year. In parts of western and southeastern Michigan, ozone concentrations exceed federal Standards. As a result, the EPA has designated three counties along the Lake Michigan shoreline and seven counties in southeastern Michigan as ozone nonattainment areas.