Even when smokers roll down windows and flip on fans, they expose car passengers to hazardous levels of second-hand smoke, says a new Canadian study that buttresses efforts to ban smoking in automobiles with children.
University of Waterloo researchers found that levels of second-hand smoke in vehicles with the windows up exceeded U.S. Environmental Protection Agency guidelines by up to 100 times in just 20 minutes of burning a cigarette. When drivers lowered windows halfway, the plume still surpassed EPA limits for 24-hour fine-particle exposure by six times.
The principal researchers, Taryn Sendzik and Geoffrey Fong, were astounded by their own findings, contained in a report by the provincial Ministry of Health's Ontario Tobacco Research Unit.
"We had to make sure the machines weren't broken," said Dr. Fong, a University of Waterloo psychology professor and principal investigator for the Ontario Institute for Cancer Research. "We eventually had to switch machines because the ones we use to monitor smoky bars couldn't actually record levels this high."
Rolling down all the car's windows and turning the fan on were other scenarios examined in the study.
Until now, advocates of automobile smoking bans could cite relatively few studies that looked directly at cigarette smoke in cars.
"This study does provide a compelling reason for provinces to act faster to enact legislation," said Rob Cunningham, senior policy analyst with the Canadian Cancer Society.
Ms. Sendzik had a personal impetus for launching the study. She still recalls sitting in the back seat of the family car as a kid while both her parents smoked in the front.
"I remember coughing and my parents rolling the windows down," said Ms. Sendzik, a grad student. "It kind of emerged from that idea."
The researchers tested 18 smokers puffing under five different ventilation scenarios.
A car with its windows rolled up registered 11 times the particulate of the average smoky bar.
"That's particularly relevant to us and our cold winters when rolling down the windows isn't an option," Mr. Cunningham said.
Other scenarios included rolling down all the car's windows, turning the fan on and cracking open one window halfway.
The study has particular relevance for children. Researchers positioned the monitor in the rear seat at the approximate height of a toddler's head.
They also noted that children breathe more rapidly than adults, absorbing more pollutants in their lungs.
Dr. Fong and Ms. Sendzik embarked on the study three years ago, well before the town council in Wolfville, N.S., voted in November to become the first jurisdiction in the country to ban smoking in cars carrying children under 18.
That history-making bylaw prompted provincial governments to do the same. Nova Scotia brought in a ban in December. Ontario, British Columbia, New Brunswick and Manitoba are all considering similar measures.
Smokers' rights advocates oppose the new laws and question any science that might be used to support the bans.
"We tell all our members not to smoke in the presence of kids, in cars, in homes, ever," said Arminda Mota, president of MyChoice.ca, a smokers' advocacy group funded by Imperial Tobacco. "These health zealots - what's next, are they going to ban adults from giving junk food to kids? Are they going to come to our houses and see how you cook your meals? While they're there they might as well come to your bedroom and check out how you do it. Is this a free country?"
Mr. Cunningham dismissed that line of reasoning. "For 40 years, the slippery-slope argument has been used against every tobacco measure," he said.
"That's to be expected. It's pretty hard to argue that children should be exposed to poison."
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