Outdoor smoking: fair or foul?BMJ 2019; 366 doi: https://doi.org/10.1136/bmj.l5754 (Published 30 September 2019) Cite this as: BMJ 2019;366:l5754
How common are outdoor smoking bans?
While much less common than indoor bans, they are catching on. This summer, Sweden banned smoking in many outdoor spaces, including playgrounds, train platforms, and restaurant patios. The regional government of Catalonia has proposed a similar ban, prompting protests from restaurant owners in Barcelona. Smoking has been banned on the grounds of more than two thirds of NHS hospitals in England, according to Public Health England.1
What are the arguments for outdoor bans?
Outdoor smoking bans may make smoking less convenient and visible—possibly giving smokers more reasons to quit and giving non-smokers, especially young people, fewer chances to see smoking as a normal, acceptable habit.
The bans might also reduce direct health harms to non-smoking bystanders. The position of major public health groups, including the World Health Organization2 and the US Centers for Disease Control and Prevention (CDC),3 is that there isn’t a risk free level of exposure to tobacco smoke, and that even brief exposures can cause harm.
What’s the evidence outdoor bans curb smoking?
Bans in parks and on beaches do reduce smoking in those locations, a number of studies show.4 College smoking bans in the US and UK that included outdoor spaces appeared to reduce both the number of on-campus smokers and the number of cigarettes they smoked, according to a review of 19 studies.5
“Outdoor bans have more to do with the denormalisation of smoking than with the protection of bystanders from side stream smoke,” says Ronald Bayer, professor and co-chair at the Center for the History and Ethics of Public Health at Columbia University’s Mailman School of Public Health in New York.
“To the extent that there are public health benefits, they are related to making quitting more likely,” he says.
What evidence is there for direct health harms of outdoor smoke?
While smoke levels outside can vary widely—depending on a range of factors including the number of smokers present and the wind direction—a review of 18 studies published in 2013 found that smoking in outdoor areas adjacent to indoor smoke free areas increased concentrations of smoke in both locations.6
It’s well established that chronic exposure to secondhand smoke can cause disease and premature death in non-smokers. The risks for children include more frequent and severe asthma attacks; the risks for adults include more heart attacks, strokes, and lung cancer, the CDC says. Hospitality workers and those who live with smokers may be at especially high risk.7
But even intermittent, low level exposure has been linked with stroke and heart attack in people with pre-existing heart disease, says Steven Schroeder, professor of medicine and director of the Smoking Cessation Leadership Center at the University of California San Francisco.
In studies carried out in England, Scotland, and the US, comprehensive smoking bans focused on indoor spaces, including restaurants and bars, have been linked with improvements in respiratory health and declines in heart attacks and stroke.3
The degree to which those risks are further reduced when smoking is banned outdoors would be difficult to prove, Schroeder says. Common sense dictates that a single person smoking on a beach poses a different risk than dozens of people smoking in a crowded outdoor café, he notes.
How do the arguments apply to electronic cigarettes?
Outdoor bans could help to denormalise vaping and make it less convenient, Schroeder says. Some vaping devices, however, can be used surreptitiously, making it easier for users to ignore the rules and less likely for others to notice the practice, he says.
In an evidence review published in 2018, Public Health England said that “to date, there have been no identified health risks of passive vaping to bystanders.”7
Schroeder says the science on any secondhand risk is not settled and is complicated by the fact that vaping devices and the substances used in them vary greatly.
I have read and understood BMJ policy on declaration of interests and have no relevant interests to declare.