Tropospheric Ozone - Bad Nearby!

Since tropospheric ozone is naturally occurring, small amounts do not harm humans and other organisms on Earth’s surface. The Environmental Protection Agency (EPA) has classified ground-level ozone as a criteria pollutant. Anthropogenic sources have caused ground-level ozone levels to rise. Tropospheric ozone appears on WeatherSTEM station pages using Dobson Units, or DU’s.

This map of displays the tropospheric ozone distribution in June, July, and August from 1979 to 2000. Considerably more ozone pollution exists in the Northern Hemisphere than in the Southern Hemisphere year ’round. In low latitudes in the Southern Hemisphere, ozone concentrations are most pronounced during austral spring (September-November. Image based on data from Jack Fishman, NASA Langley Research Center.) Source: Tropospheric Ozone | NASA