Doctors in Britain measured concentrations of fine particles in cars driven by 17 people, 14 of them smokers, using an electronic monitor on the back seat.

 

The volunteers were asked to follow their normal smoking habits as the smoke levels in their car were monitored over three days.

Out of 104 journeys — average time 27 minutes — 63 were smoke-free.

 

During smoking journeys, levels of fine particles were 85 microgrammes per cubic metre on average, compared to guidelines of 25 mcg/cu. metre for indoor pollution set by the UN’s World Health Organisation (WHO).