Ozone
Ozone is created and destroyed naturally in the stratosphere the second layer of the atmosphere. In the stratosphere, it protects us from harmful UV radiation from the sun. This is often referred to as the 'good ozone'. The ozone in the troposphere is often referred to as the 'bad ozone' due to its harmful effects to humans.
Increases in the troposphere's ozone near the earth surface is caused by human pollution.Near the Earth’s surface, ozone is produced in chemical reactions involving naturally occurring atmospheric gases with sunlight. Ozone is also produced from human pollution sources. Fossil fuel (coal, oil, and natural gas) combustion is a main source of man-made ozone in the troposphere.