Motorists who smoke while driving can produce levels of indoor air pollutants that greatly exceed World Health Organization standards.
That’s the chief finding of a new study that suggests smoking in cars can put the health of passengers — particularly children — at greater risk, even when the windows are open or air conditioning is switched on.
"Children are likely to be at greater risk from [secondhand smoke] exposure due to their faster breathing rates, less developed immune system and their inability to move away from the source in many home and car settings," the researchers said.
The study, published in the journal Tobacco Control, noted several other countries — including Canada, the U.S., Australia, Cyprus, and South Africa — have introduced state or national legislation to ban smoking in cars in which children are passengers.
To gauge the level of secondhand smoke in vehicles, the researchers measured levels of fine particulate matter every minute in the rear passenger area during car rides made by smokers and non-smokers over a three-day period.
Seventeen drivers, 14 of whom were smokers, made 104 treks, lasting from 5 to 70 minutes, with an average duration of 27 minutes.
Although smokers tended to open car windows to provide some ventilation, pollution levels still exceeded the maximum safe limit recommended by the World Health Organization at some point during all car journeys during which somebody smoked.
The researchers noted exposure to secondhand smoke is linked to several children's health problems, including sudden infant death, middle ear disease, wheeze and asthma. The U.K.’s Royal College of Physicians Tobacco Advisory Group has called for a ban on smoking in cars.