Nitrogen dioxide (NO
2) is one of a group of highly reactive gases known as oxides of nitrogen or nitrogen oxides (NO
x). Other nitrogen oxides include nitrous acid and nitric acid. NO
2 is used as the indicator for the larger group of nitrogen oxides.
The major cause of NO
2 in the air is a result of incomplete combustion of fossil fuels with the highest concentrations resulting from diesel vehicles. Coal mining, buses and other diesel vehicles create the greatest hazard for ambient air exposure in mines, tunnels, and enclosed spaces such as repair garages. Also, NO
2 along with nitric oxide, carbon dioxide and sulphur dioxide are all pollutants from power generation. ....