Some bars and restaurants have been exempted from smoking bans because theyre installed high tech ventilation systems to remove cigarette smoke. But just how effective are those sysstems?

Two researchers, James Repace and Dr. Ken Johnson, say theyve studied these expensive systems and found them ineffective at removing dangerous secondhand smoke. In a new study, Repace and Johnson found that these high-tech systems were no match for secondhand smoke and may, in fact, perform worse than standard "dilution" ventilation.

The study looked at air quality before and after a smoking ban in a restaurant/bar in Toronto, Canada, and compared the level of smoking-related cancer-causing chemicals and toxic particles in the air of non-smoking and smoking sections of two dining/drinking establishments in Mesa, Arizona.

"This study proves that dining in a restaurant or bars non-smoking section does not significantly reduce exposure to smoke-related pollutants, even in those few establishments that use these sophisticated, expensive ventilation systems," said Repace, who is Adjunct Professor at Tufts University School of Medicine and a secondhand smoke consultant.

"Smoking bans remain the only viable option that protects the health of non-smokers and hospitality workers," he said.

Since a hospitality industry-funded study was being heavily promoted to ventilation engineers as proving the efficacy of these systems, Repace and Johnson decided to publish their contrary results in a ventilation society journal devoted to discussion of practical solutions to indoor air quality problems.

The study is the lead technical article in the Fall 2006 issue of IAQ Applications, a peer-screened journal of the American Society of Heating, Refrigerating and Air-Conditioning Engineers.

Breast Cancer Risk

Johnson, Research Scientist/Epidemiologist with the Centre for Chronic Disease Prevention and Control, the Public Health Agency of Canada, is one of the world's leading experts in breast cancer from secondhand smoke.

His work provided the foundation for a report by the State of California, which found that secondhand smoke nearly doubles breast cancer risk. Repace, whose groundbreaking research on secondhand smoke led to the Environmental Protection Agencys policy interest in indoor air pollution, recently published a widely quoted study demonstrating that the level of cancer-causing particles in smoke-filled bars is much higher than it is on diesel truck-choked highways.

Displacement ventilation has been proposed as a way to allow non-smokers and smokers to co-exist, because it does not re-circulate smoky bar air and theoretically removes pollutants from restaurant non-smoking sections.

It has been promoted by hospitality industry associations and tobacco interests as part of a strategy designed to thwart the adoption of smoking bans. This study is one of the first to look at whether these systems provide sufficient protection.

False Sense of Security

"These exotic ventilation systems give restaurant and bar owners a false sense of security," says Repace. "They feel they are protecting their employees and customers, even though deadly respirable toxins from tobacco smoke remain in the air."

Repace and Johnson measured particulate polycyclic aromatic hydrocarbons (PPAHs), common carcinogenic byproducts of tobacco smoke, and respirable suspended particles (RSPs), disease-causing substances found in tobacco smoke in the three restaurant/bars smoking and non-smoking sections.

In the Toronto establishment (Black Dog Pub), measurements were taken before and after its owner banned smoking; the Black Dog abandoned reliance on its expensive non-recirculating system after operating it for years and voluntarily went smoke-free.