To ask the Secretary of State for the Environment, pursuant to his answer of 6 June, Official Report, column 107, if the research being undertaken into the reduction of the pollutants benzene and particulates with regard to ventilation in underground car parks takes into account their relationship with unleaded petrol and catalytic convertors. [32370]

The research referred to in my hon. Friend's answer of 6 June is monitoring the actual levels of these pollutants found in car parks in use. Car park usage reflects the types of vehicles currently being driven, including vehicles using unleaded petrol and fitted with catalytic convertors.