Car drivers and passengers inhale two to three times more air pollution than pedestrians and cyclists, according to UK Government research.

Cars effectively travel in a tunnel of pollution, breathing in fumes from the cars in front. Rush hour conditions create the highest levels of in-car pollution, but motorway driving generates increased levels of nitrogen oxides. Although they breathe faster as they pedal, cyclists receive less pollution because pollution levels are lower at the edge of the road. Pedestrians receive the lowest pollution of all.

The report also claimed that people travelling by bus inhale less pollution, but did not explain why.