What Is Ozone?
- Good Ozone. Ozone occurs naturally in the Earth's upper atmosphere-6 to 30 miles above the Earth's surface-where it forms a protective layer that shields us from the sun's harmful ultraviolet rays. This beneficial ozone is gradually being destroyed by manmade chemicals. An area where the protective "ozone layer" has been significantly depleted-for example, over the North or South pole-is sometimes called "the ozone hole."
- Bad Ozone. In the Earth's lower atmosphere, near ground level, ozone is formed when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources react chemically in the presence of sunlight. Ozone at ground level is a harmful air pollutant.
This article was published by AirNow.Gov, copyright 2006.Air Purifiers that Produce Ozone May Be Hurting Your Health
What is Ozone?
How Does "Bad" Ozone Affect Human Health and the Environment?
Ozone's Effects on Human Health
Production of harmful ozone plague ion-generating products sold as air cleaners
Ozone Generators that are Sold as Air Cleaners: An Assessment of Effectiveness and Health Consequences
Ozone: Nature and Sources of the Pollutants
Ozone Fact Sheet