Cars are sources of air pollution problems, most of which are important from the vehicle. Carbon monoxide, hydrocarbons, nitrogen oxides And sulfur About 55% of the hydrocarbons from the exhaust woven 25% from crankcase and 20% of the volatility in the carburetor. And fuel tanks Oxides of nitrogen is Nitric oxide (NO), nitrogen dioxide (NO2) and nitrous oxide (N2O) is almost entirely out of the exhaust. Directly toxic to humans There is a kind of super unleaded gasoline has increased the amount of lead in the air as well.