Onsite cannabis consumption laws rarely ensure clean indoor air

As more and more states legalize adult-use cannabis, the issue of marijuana lounges and other forms of onsite consumption have come to the fore. Like with tobacco smoke, the levels of indoor air pollution when people are smoking (or vaping) marijuana are substantial.

The American Society for Heating, Refrigeration and Air Conditioning Engineers (ASHRAE), which writes standards for ventilation systems, issued a standard that made the point that it was impossible to achieve acceptable indoor air quality through ventilation when people are smoking. This standard helped accelerate passage of (tobacco) smokefree laws because it showed that ventilation could not “solve” the problem of secondhand smoke.

Now, in debates over public indoor marijuana consumption, the issue of secondhand exposure (to cannabis smoke and aerosol) has emerged as an important issue. Thomas Rotering, Lauren Lempert, and I just published “Emerging Indoor Air Laws for Onsite Cannabis Consumption Businesses in the U.S.” in American Journal of Preventive Medicine that presents a survey of how state and local policy makers are handling this issue.

While some states do not allow indoor public consumption, many delegate that decision to localities. Although the only effective means of preventing the health problems associated with secondhand smoke and aerosol is to require a smoke-free environment, most local laws that permit onsite cannabis consumption businesses either do not address secondhand exposure or call for ventilation or engineering requirements that, according to the ASHRAE standard, do not protect health.

Strong smoke-free cannabis laws, like smoke-free tobacco laws, can reduce the health burdens of secondhand cannabis smoke. Policymakers may be unaware that ventilation and other engineering interventions cannot fully protect workers and patrons. Where onsite smoking or vaping is permitted, even measures such as truly separate indoor and outdoor smoking areas may reduce but not eliminate secondhand exposure to patrons, staff, and residents.

Health authorities and local leaders should educate policymakers on the science of secondhand smoke remediation and advocate for the same standards for secondhand cannabis smoking and vaping that apply to tobacco, particularly because other cannabis administration modes that do not pollute the air could be permitted without harming bystanders.

Here is the abstract:

Introduction.  Secondhand cannabis smoke, like secondhand tobacco smoke, creates unhealthy indoor air quality. Ventilation and engineering techniques cannot reduce this pollution to healthy levels, and complete smoke-free policies are the only way to provide healthy indoor environments. Even so, multiple state and local governments have begun to allow indoor smoking of cannabis in businesses.

Methods.  A systematic search of Lexis Advance, NewsBank, and government websites for U.S. state and local laws passed between November 6, 2012 and June 10, 2020 that permit and regulate onsite cannabis consumption businesses was conducted in February–July 2020.

Results.  In total, 6 of 11 states and the District of Columbia that legalized adult-use cannabis as of June 10, 2020 allowed onsite consumption and ≥56 localities within these 6 states allowed onsite cannabis consumption. Only 9% (5/56) of localities ban indoor smoking in these businesses; 23% (13/56) require indoor smoking to occur in physically isolated rooms. Other common local legal requirements address onsite odor control, ventilation/filtration, and building location.

Conclusions.  The majority of the localities that allow onsite cannabis consumption do not explicitly prohibit smoking or vaping inside. Policymakers should be made aware that ventilation and other engineering interventions cannot fully protect workers and patrons. Health authorities and local leaders should educate policymakers on the science of secondhand smoke remediation and advocate for the same standards for secondhand cannabis smoking and vaping that apply to tobacco, particularly because other modes of cannabis administration do not pollute the air.

The full citation is: Rotering T, Lempert L, Glantz S. Emerging Indoor Air Laws for Onsite Cannabis Consumption Businesses in the U.S. Am J Prev Med 2021; Epub ahead of print 13 Aug 2021. https://doi.org/10.1016/j.amepre.2021.05.012. It is available for free here.

Published by Stanton Glantz

Stanton Glantz is a retired Professor of Medicine who served on the University of California San Francisco faculty for 45 years. He conducts research on tobacco and cannabis control and cardiovascular disease/

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