Automobiles and pollution

While the motor car has become an indispensable part of modern life, there is increasing concern about its environmental impact, particularly the negative effects of automotive exhaust emissions on air quality and human health. It has long been acknowledged that pollutants emitted from gasoline-driven vehicles contribute to a decline in air quality. Carbon monoxide, nitrogen oxide and hydrocarbons are all known to be toxic to humans or damaging to the environment.

The proportion of pollutants in the air which are directly attributable to vehicle emissions has risen significantly in line with the growth in car ownership and the increase in the number of kilometres driven per car.

Sources of the principal pollutants:
  CO NOx HC
Gasoline vehicles 90 % 52 % 40 %
Domestic 5 % 3 % 2 %
Power stations 1 % 26 % < 1 %
Industry 4 % 11 % 56 %
Others - 8 % 1 %