§ Mr. Matthew TaylorTo ask the Secretary of State for the Environment, Transport and the Regions what estimate his Department has made of the effect that reducing the benzene content of petrol would have on benzene emissions. [1000]
§ Ms Glenda JacksonThe evidence which has emerged as a result of the Auto Oil programme suggests that, very broadly the amount of benzene and the amount of aromatics in petrol contribute about equally to the benzene in vehicle exhaust gases, although the results can vary between vehicle types and operation. A third small source is from the partial combustion of other hydrocarbons. As a guide, therefore, a halving of the benzene content in petrol (typical UK average 2–3 per cent.) would result in approximately a one quarter reduction in exhaust gas benzene. The effect of fitting catalytic convertors to cars is much greater, however, benzene emissions being reduced by 85 per cent. compared with non-catalyst cars.