Restaurant air filters can raise soot levels in non-smoking sections

no smoking in restaurantsTRENTON, N.J. - State-of-the-art ventilation systems used to clear cigarette smoke from bars and restaurants don't eliminate dangerous soot and carcinogens and can even push their levels higher in nonsmoking sections than in smoking areas, researchers concluded.

Their findings from three restaurants in a little-studied field come just a week before voters in Arizona, Nevada and Ohio consider dueling smoking-related initiatives. Ballots in each state include a tough ban on smoking in public places and a more lenient proposal — with exemptions for bars and casinos — backed by industry groups.

Two of the restaurants studied were Mesa, Ariz., establishments that had claimed their ventilation systems would comply with that city's smoke-free restaurant law.

 But in one of those, contaminants in the nonsmoking sections were higher than in the bar, said lead researcher James Repace, a secondhand smoke expert and visiting professor at Tufts University School of Medicine. And in the other restaurant, the nonsmoking section had very high levels of soot.

Repace said evidence showed the complex, difficult-to-maintain ventilation systems were not working properly.

Unlike older ventilation systems that mainly dilute smoky air with fresh air, displacement systems use cooler air, ideally pumped in at floor level, to force hot, smoky air up to ceiling ducts.

"They've been heavily promoted by the tobacco industry" and the casino industry as a way to accommodate both smokers and nonsmokers, Repace said.

Need for 'tornado-like ventilation'
"I don't think it is possible for somebody to come up with a system that works," he said. "You'd need tornado-like ventilation."

In one Mesa restaurant, the average evening level of soot — inhalable particles that raise the risk of heart and lung disease — was three times higher in the nonsmoking section than in the smoking bar. The level of cancer-causing chemicals in tobacco smoke was 50 percent higher than in the bar.

A 1999 Finnish study of four restaurants with older ventilation systems had similar results, Repace noted.

A third restaurant he tested in Toronto had soot and carcinogen levels in its nonsmoking section much lower than in the bar area, but the bar had much higher contaminant levels than six bars with old-style ventilation previously tested by Repace. After the Toronto restaurant banned smoking entirely, a re-test found carcinogen and soot levels had fallen sharply.

Repace's results were published Tuesday by an engineering journal and funded by the Robert Wood Johnson Foundation, a New Jersey-based health care philanthropy.

"They demonstrate that these systems do not seem to be effective in controlling contaminants in the nonsmoking section," said Patrick Breysse, an environmental health sciences professor at Johns Hopkins Bloomberg School of Public Health.

Gil Cormier, chairman of American Industrial Hygiene Association's indoor air quality committee, agreed with the study's conclusions. "Ventilation systems over time degrade" and stop functioning as designed, he said.

Price Industries Inc., a top maker of displacement ventilation systems, said they significantly improve air quality but are "not intended to be a panacea."

In June, the U.S. Surgeon General reported that "separating smokers from nonsmokers, cleaning the air, and ventilating buildings cannot eliminate exposures of nonsmokers to secondhand smoke." The report noted the top U.S. standard setters on ventilation, the American Society of Heating, Refrigerating and Air-Conditioning Engineers — which published Repace's study — concludes that ventilation technology cannot remove smaller particles or gases found in secondhand smoke.

Those conclusions and Repace's findings are consistent, said Terry Pechacek, a Centers for Disease Control and Prevention scientist who worked on the Surgeon General's report.

Repace said few places had the newer ventilation systems when he did measurements for his study, between December 2002 and December 2004, but many casinos now have them.

Copyright 2006 The Associated Press.



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