Nitrogen Dioxide

Ozone

Carbon Monoxide

Sulfur Dioxide

Particulate Matter

Lead
 

Nitrogen Dioxide - NO₂
Nitrogen oxides (NO_x) are created by a reaction between nitrogen and oxygen when fossil fuel is burned at a high temperature. Some nitrogen oxides in the atmosphere form nitrogen dioxide (NO₂) which has been proven to be very toxic to life and is therefore specifically regulated. NO₂ is the brown, poisonous haze that makes city skies hazy and muddy looking. It is a major ingredient of ozone which is the primary component of smog.

Where
More than 3/4ths of the nitrogen oxides in the air are produced by leftover unburned fuels from cars, trucks and other vehicles. Electric utilities, oil refineries, and industrial boilers produce the rest.

Effects
Nitrogen oxides contribute to ozone and acidic fallout like acid rain and snow which harm crops, forests and aquatic life. They also form nitrogen dioxide in the air that irritates the lungs, causes bronchitis and pneumonia, and lowers resistance to respiratory infections.

Back to Criteria Pollutants Top Level