What are the origins and environmental implications of

pollutants in car exhaust gases?

By Katie Dowler and Melissa White

Carbon Monoxide (CO)

How is it formed?• When a carbon reaction doesn’t have enough oxygen and

therefore is incomplete carbon monoxide is formed. It is normally a carbon dioxide reaction.

• Car exhaust emissions contain carbon monoxide from incomplete burning of fuel in the engine.

What effects does it have on the environment?• Increases the global temperature (increase in global warming)• Combines with Haemoglobin which affects the respiratory

system

Carbon Dioxide (CO2)

How is it formed?• When petrol burns, the carbon in it forms a covalent

bond with oxygen in the air to form carbon dioxide.

What effects does it have on the environment?• Carbon dioxide is mainly a problem as a greenhouse gas as this contributes to global warming• It traps the energy from the sun in the atmosphere, therefore heating the earth up• Contributes to acid rain

Sulfur Dioxide (SO2)

How is it formed?• Sulfur dioxide is formed when compounds containing

sulfur are burnt.

What effects does it have on the environment?• Effects plant, tree and crop productivity• Combines with water to form acidic products (contributes to acid rain)• Forms atmospheric particles

Nitrogen Oxides (NOx)

How is it formed?• During combustion at high temperatures• Nitrogen and oxygen gases in the air will not react on

their ownWhat effects does it have on the environment?• Helps to form acid rain• It adds to greenhouse gases which contributes to global warming• Effects the growth of plants• Can react with other pollutants to form toxic chemicals which will harm the environment

Un-burnt Hydrocarbons (CxHy)

How is it formed?• Incomplete combustion of petrol in car exhausts• Leakage from petrol tanks as the petrol vapourises and escapes into the air

What effects does it have on the environment?• Some hydrocarbons are toxic• Assists the formation of the ozone layer• Produces air pollutants which can cause cancer

ParticulatesHow is it formed?• Produced by incomplete combustion of the hydocarbon

fuels in diesel

What effects does it have on the environment?• Reduces visibility in the area (haze)• Damaging forests and plants• Contributing to acid rain• Makes lakes and oceans more acidic