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Vehicle Emission Controls

Through emissions of nitrogen oxides, cars and other road vehicles are major contributors to acidic emissions which cause acid rain. In all countries of the industrialised world, the number of vehicles on the roads has been continually increasing since the 1970s. With a large rise in traffic numbers, it becomes increasingly important to keep pollutant emissions to a minimum. There are presently a number of ways in which road traffic pollution can be reduced, including the use of emission control technology solutions.

Since January 1993, all new cars sold in the European Union have been fitted with a catalytic converter. Most catalytic converters lead to a dramatic reduction in emissions of nitrogen oxides, as well as other harmful pollutants.

Exhaust Gas Recirculation involves returning exhaust air to the fuel inlet, which results in a reduction in peak engine temperatures and emissions of nitrogen oxides from petrol vehicles.

Smaller, lighter cars use less fuel and hence produce less pollution. Technological development using lighter materials for construction may therefore reduce emissions.

The above technologies all provide a reduction in emissions from vehicles. Electric transport is an alternative development that could lead to a large reduction in acidic pollution at ground level, if it became more wide spread. Electric transport produces no emissions at the point of use, although pollution is emitted during the production of electricity from power stations. The main drawback for electric vehicles is the need to recharge batteries. In addition, although they have lower fuel and maintenance costs than petrol and diesel, at present they require a higher capital investment.

The technical fixes such as those outlined above need to be combined with management schemes to reduce traffic in city centres, education to encourage the public to use their cars less, and the further development of alternative fuels that are not harmful to the environment.