A special filter in a car engine used to lower the exhaust pollution level; it can break down many exhaust pollutants.

The catalytic converters are used to reduce the amount of carbon dioxide, carbon monoxide, hydrocarbons and nitrogen oxide. Platinum, palladium and rhodium are used in catalytic converters. Chemical reaction and temperature makes these emission substances to carbon and nitrogen. The emissions are also reduced significantly.

The other problem produced here is the poisonous heavy metal platinum or palladium will be released into the environment.

The fine carbon particles are also dangerous to our health.