Well, like so many things, it depends. We have heard that the ozone layer protects us from the harmful rays from the sun, and that is a good thing. The ozone layer occurs in the stratosphere from 10 to 30 miles above the surface of the earth. Many products such as the propellants in hair spray and oral inhalers have been blamed for harming this layer, and have been pulled from the market.
However, ozone at ground level can be a very bad thing, especially for those of us who have enough trouble breathing without any outside interference! Sunlight and hot weather combine with auto exhaust, gasoline vapors, industrial emissions, and chemical solvents to form harmful levels of ozone. Ground-level ozone is the primary constituent of smog.
Many urban areas tend to have high levels of "bad" ozone, but even rural areas are subject to increased ozone levels because wind carries ozone and the pollutants that form it hundreds of miles away from their original sources.
Exposure of 0.1 to 1 part per million of ozone in the air we breathe produces headaches, burning eyes, and irritation to the respiratory passages. One ppm (part per million) is roughly equivalent to one second of time in approximately 11½ days.
Web sites are available that will give us air quality for most regions, especially larger metropolitan areas.
AIRnow.gov is a good place to start. From there, you should be able to zero in on your area.
Uncle Jim & Aunt Mary