What is ground-level ozone and how can I be exposed to it?
Ozone is a gas that is naturally found in earth’s upper atmosphere, where it forms the ozone layer. The ozone layer blocks some of the sun’s harmful ultraviolet (UV) rays. To learn more, see UV Radiation below. Ground-level ozone is ozone in the lower atmosphere, close to the Earth’s surface. This is one of the main components of smog. Ground-level ozone is formed when sunlight and heat cause chemical reactions between nitrogen oxides and volatile organic compounds (VOCs). VOCs are pollutants released by motor vehicles, factories and power plants, and chemicals such as paints and cleaners. Ground-level ozone is a pollutant that can harm the environment, crops, and human health.
