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February 23, 2007

High Exposure to Secondhand Tobacco Smoke Detected in Baltimore Bars

Workers and patrons of Baltimore bars are exposed to high levels of secondhand smoke, according to two studies conducted by researchers at the Johns Hopkins Bloomberg School of Public Health. Results of the first study showed that the average level of particulate matter pollution in the bars surveyed was at least 10 times higher than the Environmental Protection Agency’s (EPA) outdoor air safety levels. A second study examining hair samples from non-smoking bar employees indicated that employees working in bars that allowed smoking absorbed higher levels of nicotine compared to employees working at smoke-free bars.

Secondhand smoke from cigarettes pollutes indoor places with particles where people are smoking. Breathing secondhand smoke is known to cause lung cancer and heart disease, as well as lung problems in children. A 2006 Surgeon General’s report on the health effects of secondhand smoke concluded that there are no safe levels of exposure to passive cigarette smoke.

“These findings show that employees in bars where people are smoking are personally exposed to tobacco smoke from others. Smoke-free bars can provide complete protection for employees and non-smoking patrons,” said Ana Navas-Acien, PhD, MD, an assistant professor with the Bloomberg School’s Department of Environmental Health Sciences.

“The results are consistent with those of larger studies we’ve conducted in bars in South America,” said Patrick Breysse, PhD, professor in the Bloomberg School’s Department of Environmental Health Sciences. 

The concentrations of particulate matter were based on air samples taken from 14 Baltimore bars on January 26 and 27. Using hand-held monitors, a team of six researchers sampled the air in each bar for approximately 30 minutes. They also observed how many people were in the bar and how many were smoking. The monitors remained on after the researchers left the bars to measure the concentration of small particles in the outdoor environment.

In all of the bars surveyed, particulate matter concentrations were higher than the EPA’s outdoor safety level of 35 micrograms per cubic meter. The average concentration of particulate matter in the air inside the bars was 11 times higher than outside. In all of the bars, only a small percentage of the patrons were smokers. One bar measured had a single smoking patron and an indoor concentration of small particles 19.5 times higher than the outdoor concentration. “These findings show that workers are continuously exposed to high levels of air pollution indoors,” said Heather Wipfli, MS, lead author of the study and project manager with the Bloomberg School’s Institute for Global Tobacco Control.

The second study specifically measured secondhand smoke inside Baltimore bars by measuring airborne nicotine during a seven-day period. Up to four non-smoking employees from each bar donated samples of their hair to measure personal exposure to secondhand smoke.

Air nicotine was detected in all the bars where smoking was allowed, indicating that involuntary exposure to tobacco smoke occurs in Baltimore bars.  No nicotine was detected in the hair of non-smoking employees working in a smoke-free bar, while high levels of nicotine were detected in the hair from non-smoking employees working in bars where smoking is allowed.

“These findings show once again that cigarette smoking is a very strong source of particles indoors.  The scientific evidence shows that the people breathing secondhand smoke indoors face serious health risks,” said Jonathan Samet, MD, MS, director of the Institute for Global Tobacco Control and professor and chair of the Bloomberg School of Public Health’s Department of Epidemiology.

The study was conducted with support from the American Cancer Society and Institute for Global Tobacco Control at the Johns Hopkins Bloomberg School of Public Health.

Public Affairs media contacts for the Johns Hopkins Bloomberg School of Public Health: Kenna Lowe or Tim Parsons at 410-955-6878 or