§ Mrs. Ann TaylorTo ask the Secretary of State for the Environment if he will give an estimate of the impact of the introduction of catalytic converters on United Kingdom emissions of nitrous oxide from road transport.
§ Mr. MacleanBefore the introduction of catalytic converters on cars, road transport made a small contribution to United Kingdom emissions of nitrous oxide. Measurements made on the exhaust emissions of cars fitted with catalytic converters show that emissions are a factor of 3–5 higher. Nevertheless, even when all the United Kingdom vehicle fleet is equipped with catalytic converters, road transport emissions will still be small compared with other sources, particularly soils and nylon manufacture.
Catalytic converters will in any case reduce emissions of other oxides of nitrogen by around 75 per cent.