Ozone in the stratosphere absorbs some of the Sun's biologically harmful ultraviolet radiation. Because of this beneficial role, stratospheric ozone is considered good ozone. In contrast, excess ozone at Earth's surface that is formed from pollutants is considered bad ozone because it can be harmful to humans, plants and animals. The ozone that occurs naturally near the surface and in the lower atmosphere is also beneficial because ozone helps remove pollutants from the atmosphere.