TORONTO — Nicotine levels are “strikingly higher” in smokers’ cars than in non-smokers’ vehicles, and even exceed those found in public or private indoor spaces where tobacco use is allowed, a study has found.
Researchers at the Johns Hopkins Bloomberg School of Public Health tested air nicotine concentrations in smokers’ vehicles and found they were twice as strong as levels measured by other studies in public and-or private places and up to 50 per cent higher than measurements taken in restaurants and bars that permit smoking.
“We’re interested in what the second-hand smoke exposure might do to a non-smoker travelling in a car with a smoker,” said senior author Dr. Patrick Breysse. “And it seems like the car is probably the last environment where people have begun to think about the risk of second-hand smoke exposure.”
“The car represents a unique sub-environment because it’s a confined space and the opportunity for elevated exposures, even though they’re for a shorter period of time, the exposures are greater,” Breysse said from Baltimore, adding that children are particularly at risk.
“So it’s probably something we need to be worried about.”
The researchers studied the vehicles of 17 smokers and five non-smokers who commuted to and from work for 30 minutes or longer.
Two passive airborne nicotine samplers were placed in the vehicles - one on the front passenger seat headrest and one in the back seat behind the driver - for a 24-hour period. In all, they analyzed 44 samplers.
“And we found that for each cigarette smoked in the car, there was about a doubling in the airborne nicotine concentration,” said Breysse, noting that the study took into consideration the size of each vehicle and the use of ventilation.
“Most people drive with the windows up and the air conditioning on,” he said. “We found that rolling the windows half-way down reduced the exposure … but not as low as we expected.”
The researchers, whose work is published Tuesday in the British Medical Association journal Tobacco Control, tested nicotine because it is a good marker for the other chemicals found in second-hand smoke.
Other studies have measured air-borne particles of toxic and cancer-causing chemicals known to be emitted from smoking, but those levels can be skewed by other sources, including those pumped into the environment from surrounding traffic.
“Nicotine is very unique to second-hand smoke exposure,” he said. “So by measuring that, we’re sure we’re assessing what the contribution of the smoke is.”
Dr. Peter Selby, clinical director of the addictions program at the Centre for Addiction and Mental Health in Toronto, said the research confirms what other studies have shown, that there is significant exposure to second-hand smoke in confined spaces - and a car’s no different.
“It’s a pivotal study in the sense that it helps raise the awareness of many health professionals as well as policy makers that we need to do something about this issue around smoke in cars,” said Selby, who was not involved in the research.
Many countries have introduced legislation banning smoking in public places, but most do not apply to tobacco use in cars. In Canada, Nova Scotia and Ontario are among the provinces that prohibit smoking in vehicles carrying children.
Because of their smaller lungs and faster breathing rate, children are especially at risk from the effects of second-hand smoke, he said.
“I think we need to do something clearly for the involuntarily exposed, for example children,” Selby said. “But there’s only so much you can legislate. There’s also public education that’s required around this.”
“It’s not to say that adults are not affected either. We know they are … including smokers themselves, who often tell us they have great difficulty quitting because once they get back into their car, they often feel triggered to have a smoke.”
“So we have to help them break those connections.”
In fact, participants in the U.S. study were asked to complete a questionnaire on their attitudes toward health risks from second-hand smoke in cars and legislation to ban the practice. All agreed that smoking in vehicles posed a health risk to passengers.
Among the smokers, 53 per cent said that being unable to smoke in the car would help them to kick the habit and 93 per cent said vehicles should be smoke-free on a voluntary basis. Only seven per cent said vehicles should be smoke-free by legislation.
“We need to have a concerted effort to address smoking in cars and the risks associated with non-smoking passengers,” said Breysse. “And I think this (study) provides additional evidence suggesting that smoking should be banned in cars, with children in particular.”