The Science Behind Moving Smoking Bans Outside

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When, more than a decade ago now, smoking bans began to take effect around the world, researchers and public health officials feverishly collected data demonstrating the health benefits: lower levels of respiratory illness were reported among bar workers from Dublin to San Francisco after indoor smoking bans took effect, saliva tests revealed lower levels of nicotine concentration in hotel and restaurant workers once smokers were chucked outside, and hospital admissions for heart attack and other cardiovascular complications dropped significantly in states where indoor smoking was banned. The U.S. surgeon general’s office issued a report in 2006 emphatically declaring that: “there is no risk-free level of exposure to secondhand smoke,” and evidence confirming these findings continues to emerge almost weekly. And now, as indoor smoking bans gain traction worldwide and efforts to spread the bans to more U.S. states continue, researchers and public health officials are increasingly setting their sights on the next frontier in the battle against second hand smoke: the outdoors.

Many smokers already feel that their liberty to light up is being trimmed back—with bans moving beyond public buildings and offices to private apartments and public housing in some cities. And recent efforts, like that New York City health commissioner Thomas A. Farley, to extend the bans to public parks and beaches, and other cities’ parallel initiatives, which include parking structures and dining areas, are stirring up debate about whether the initiatives are going too far.

Reflecting on the existing scientific research on second hand smoke exposure outdoors, William Saletan of sifts through the most relevant points from two major studies on the subject (the 2006 California Air Resources Board study, and a 2007 study from Stanford). Among the findings: outdoors, second hand smoke levels vary widely and quickly, depend on the individual’s distance from a smoker (farther than 6.5 feet or 2 meters, generally reduces exposure to “background” levels), are influenced by how confined the outdoor space is (if there are walls or fences), and the concentration of smokers in a given area. The data, Saletan concludes, point to the need for a measured approach for crafting policy to reduce second hand smoke exposure outdoors. He writes:

“If you want to argue for parkwide smoking bans based on asthma or on an analogy to noise pollution, go ahead and make that case. But let’s not cloud that debate by invoking the general harm of secondhand smoke. Studies of secondhand smoke have indeed moved outdoors. Their findings support restrictions on lighting up within a few feet of other people. But they don’t warrant more than that.”

A new study published in the November issue of the Journal of Occupational and Environmental Hygiene may contribute to the debate. Researchers from the University of Georgia measured second hand smoke exposure among people sitting in the outdoor areas of bars and restaurants where indoor smoking was banned in the city of Athens, Georgia. “[T]he many indoor smoking bans established across the world have encouraged the movement of previous indoor smoking outdoors, and thus, estimating the extent of outdoor [second hand smoke] exposure of nonsmokers is a potentially significant public health issue,” they write. Over the course of six weeks in the summer and autumn of 2007, 23 non-smoking university students spent periods of six hours at a time seated in outdoor areas—including a bar, restaurant, and open area on the school’s campus—where smoking was permitted. Before and after the “hanging out” sessions, researchers measured the amount of cotinine, a metabolite of nicotine, in participants’ saliva. (Samples were collected using Salivettes, or basically plastic tubes containing cotton swabs, and sent to labs at the Centers for Disease Control for testing).

The researchers deliberately conducted the experiments on nights when sporting events would draw big crowds to the bars and restaurants. They found that, in keeping with the research highlighted by Saletan, students sitting in an open-air part of campus experienced negligible levels of tobacco exposure, while those seated in the more confined spaces at bars and restaurants, experienced significant increases in cotinine concentrations. Levels rose by 162% among students hanging out at the bar, 102% among those at a restaurant, and 16% in the control setting. Yet, in spite of the shocking statistics, overall levels of exposure for all three areas remained relatively low, and would be classified as “background” level, according to measures established by the National Health and Nutrition Examination Survey.

So what does that mean in terms of the scientific argument for outdoor smoking bans? The researchers say that additional investigation, including more precise figures about the number of smokers in a particular space, the rate of smoking and measurements in different populations are important to achieving more definitive results. But, generally speaking, hanging out in an outdoor smoking area exposes you to less second hand smoke than being in an indoor, confined space with smokers, and the more space you have between yourself and smokers, the lower levels of exposure you will have. So, this particular study doesn’t ring the death knell for outdoor smoking. But, the researchers point out, wielding the official trump card of the public health argument:

Although the increment in cotinine concentrations and, thus, the [second hand smoke] exposure levels were relatively low at the sites of interest, the current view is that there is no level of personal exposure to [second hand smoke] that can be regarded as safe. This study demonstrates the ongoing exposure of nonsmokers to [second hand smoke] outside restaurants and bars, and the limitations of indoor smoking bans alone in protecting the public from exposure to [second hand smoke] outside these establishments.

In other words, the movement to ban smoking in outdoor spaces is here to stay.