Pollutant gases such as carbon monoxide and oxides of nitrogen are produced by a car engine and are emitted through the exhaust pipe.

1. aDescribe how oxides of nitrogen are formed in car engines. [2]
2. bExplain how carbon monoxide affects human health. [2]
3. cWhy are catalytic converters fitted in car exhausts? [1]
4. dSuggest why catalytic converters contain a network of fine holes. [2]
5. eThe concentration of carbon dioxide in the atmosphere is increased by the burning of petrol in cars. State one type of environmental damage caused by this increase. [1]

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