EGEE 102
Energy Conservation for Environmental Protection

Introduction to Ozone


Ozone (O3) is a triatomic oxygen molecule gas that occurs both in the Earth’s upper atmosphere and at ground level. Ozone can be good or bad, depending on where it is found: It is a bluish gas that is harmful to breathe. Therefore, it is bad at the ground level.

Ozone in Earth's Atmosphere diagram
Ozone in Earth's Atmosphere.
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Good ozone occurs naturally in the Earth's Stratosphere (upper atmosphere) 10 to 30 miles above the Earth's surface-where it shields us from the sun's harmful ultraviolet rays called UVB band. 90% of the Earth's ozone is in the stratosphere and is referred to as Ozone Layer.

Bad ozone occurs in the Earth's lower atmosphere, near ground level, when pollutants emitted by cars, power plants, industrial boilers, chemical plants, and other sources react chemically in the presence of sunlight. Ozone pollution is a concern during the summer months, when the weather conditions needed to form ground level ozone (lots of sun and hot temperatures) naturally occur.