Cannabis Legalization Threatens Clean Indoor Air, Study Says

Most US states that permit legal on-site consumption of cannabis don’t protect clean indoor air, according to new research.

Published in the American Journal of Preventive Medicine, the paper claims that, without new policies, the years of progress achieved on protections from second-hand tobacco smoke could be undone by cannabis legalization.

Up in smoke

To assess the impact of legal cannabis smoking, the researchers from the University of California, San Francisco, analyzed the local laws of 274 jurisdictions across 11 US states and that had legalized marijuana between November 2012 and July of 2020.

Among these jurisdictions, just 56 localities in 5 states (Alaska, California, Colorado, Illinois, Michigan) permitted cannabis consumption within a cannabis business.

Of these 56 regions, 5 (9 percent) require that indoor area to be smoke-free.

Thirteen of the regions (23 percent) permit smoking in isolated rooms with certain caveats, such that smoke not drift to non-smoking areas or that there be a smoke-free employee viewing area. This approach, according to the researchers, can control cannabis smoke exposure if executed properly, but “doesn’t protect employees and patrons” from second-hand cannabis smoke exposure in smoking areas.

The remaining localities (68 percent), according to the researchers, don’t protect non-smokers from second-hand smoke because they don’t require physical separation of smoking and non-smoking areas. These laws, the researchers claim, resemble the tobacco industry’s framework by inviting smoke inside and positioning ventilation or engineering controls as second-hand smoke solutions.

“After decades of progress in clearing the indoor air of tobacco smoke, we are seeing it replaced with cannabis smoke using the same discredited arguments the tobacco industry used in its unsuccessful fight against tobacco smoke restrictions,” Stanton A. Glantz, a retired professor from the Center for Tobacco Control Research and Education and co-author of the paper, said in a statement.

“We need to learn from the past and keep the air clean for all,” he added.

In the study’s conclusion, Glantz and the other authors recommend that policymakers be made aware that ventilation and other engineering interventions are inadequate solutions to the health concerns posed by second-hand smoke from products like pre rolls, which are often wrapped in pre roll packaging. Instead, law makers should strive for the same health and safety standards currently in place to protect the public from tobacco smoke.

“While many states maintain strong tobacco smoking and vaping bans to protect public health, our research reveals that some state and local laws exempt cannabis smoke from clean air laws and open the door to smoke-filled businesses, defeating decades of public health advances,” Thomas L. Rotering, a researcher at the Center for Tobacco Control Research and Education and co-author of the study, said in a statement.

The health concerns of second-hand cannabis smoke

Cannabis smoke is known to contain many of the same chemicals present in tobacco smoke. Yet the effects of these chemicals may be altered when present with cannabinoids, according to some research.

One scientific review published in Cancer Epidemiology Biomarkers & Prevention in 2015 found no association between cannabis use and lung cancer despite marijuana smoke containing many known carcinogens in amounts comparable with those found in tobacco smoke. One explanation for this null association, as posited by the review, is that cannabinoids like THC counteract the carcinogens with their tumor-suppressant effects, which have been evidenced in several cell culture and animal models studies.

But other, more recent studies have documented the negative health risks second-hand cannabis smoke can pose.

A study published in Pediatric Research this year found that the children of regular cannabis consumers who smoke or vape come down with viral respiratory infections more often than children whose parents don’t smoke. However, other risks known to be associated with second-hand tobacco smoke, such as ear infections or asthma attacks, weren’t reported more frequently in the children of frequent cannabis users.

Another paper published in EClinicalMedicine earlier this year found that cannabis smoking raises the levels of the toxic chemicals acrylonitrile and acrylamide in the blood, but not to the same extremes seen in tobacco smokers.