The atmosphere is divided into layers. The three layers nearest the earth are called the troposhpere, stratosphere, and mesosphere.
Ozone affects people in two ways.
In the stratosphere, ozone occurs naturally and forms a protective layer which shields us from ultraviolet radiation. Sources of Ozone Pollution Ozone in the troposphere is a pollutant. There are few direct sources of tropospheric ozone. Instead, ozone is produced in the air by chemical reactions involving nitrogen oxides and volatile hydrocarbons. The main sources of nitrogen oxide pollution are motor vehicles and electricity generation using combustion processes.