Smoke levels often exceed concentrations associated with harmful effects

A study by environmental engineers at Stanford University shows secondhand smoke in California’s Native American casinos often exceeds concentrations associated with harmful effects.

The study was published online Wednesday in the Journal of Exposure Science and Environmental Epidemiology.

In a yearlong investigation, the engineers studied smoke particle concentrations during busy evenings in 36 casinos. It found that even many nonsmoking areas within the buildings contained smoke concentrations several times those found in outdoor air. One-quarter of American adults visited a casino in 2008, according to the American Gaming Association. Of the almost 60 casinos operating in California, 98 percent allow smoking.

“We did this study to warn the public that where they go and what they do in their everyday lives can impact their health,” said Lynn Hildemann, a senior author of the study and an associate professor of civil and environmental engineering. She was quoted in a Stanford Report article about the study.

“Air pollution affects human health, whether it is secondhand smoke indoors or truck exhaust outdoors. Because many people frequent smoky casinos, and many employees work there, we became interested in finding how high the pollution levels inside the buildings were.”

Over more than a year, the team of researchers discreetly made smoke particle measurements in various locations at each casino on weekend and holiday evenings – times when casinos were most likely to be crowded. Sampling each location for 30 to 60 minutes, the engineers used compact monitors that measure smoke particles in the surrounding air every 10 seconds.

In areas of casinos where smoking was allowed, average fine particle concentrations were nine times as high as in outdoor air (63 micrograms per cubic meter versus 7 micrograms per cubic meter outdoors). Similarly high averages were reported in bars and restaurants in California before the state passed laws restricting smoking indoors in 1994. The smokiest casino had an average concentration that was 26 times as high as outdoor air. The U.S. Environmental Protection Agency’s health-based standard for fine particles is an average of 35 micrograms per cubic meter over a 24-hour period. This concentration level was exceeded in 90 percent of the casinos the researchers visited.