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Cannabis Position Statement

Marijuana and Lung Health

Marijuana is currently an illegal substance in Canada, with the exception of medical marijuana, which is prescribed by a physician. The Canadian Lung Association believes that the decision to use marijuana for medical purposes is a decision between a physician and a patient. However, we recognize that the Government of Canada is taking steps to legalize marijuana and we would like to ensure that the regulatory framework takes into account the lung health of all Canadians.

The Canadian Lung Association aspires to a future free of lung disease. Prevention is imperative in making this future possible. We caution the public against smoking marijuana because of the risks it may pose to lung health.

The inhalation of smoke is harmful to lung health as the combustion of materials releases toxins and carcinogens. These are released regardless of the source – whether it is burning wood, tobacco or marijuana. Knowledge about the long-term effects of marijuana smoke is still limited but early research studies have demonstrated harm that can lead to chronic bronchitis.[i] Other studies suggest that frequent and heavy marijuana smoking is associated with cough, sputum production, wheezing and a decline in lung function. [ii][iii] Smoking of marijuana by persons who also smoke tobacco is of particular concern, as there is evidence that tobacco and marijuana smoking act synergistically to increase the risk of respiratory issues and chronic obstructive pulmonary disease.[iv]

Second-hand marijuana smoke contains many of the same toxins and chemicals found in directly inhaled marijuana smoke. [v] More research on the health effects of second-hand marijuana smoke is needed. Until this issue is addressed, the Canadian Lung Association remains concerned about the potential harmful effects – especially among vulnerable populations, such as children and youth.

Policy Recommendations:

The Canadian Lung Association recommends that the legalization and regulation process of marijuana take into account the lung health of Canadians. If marijuana is legalized in Canada, the federal, provincial and municipal governments should adopt the following policies for marijuana smoke where jurisdictionally appropriate:

  • Prohibit the sales to minors.
  • Prohibit the use in public spaces and workplaces where smoking is banned. The Canadian Lung Association believes that all Canadians should have a right to breathe clean air free of all types of smoke. For this reason, marijuana should be regulated under all smoke-free laws, including but not limited to public places, workplaces, etc.
  • Dedicate funding for research that will address acute and long-term effects of marijuana use on respiratory health. This should include funding to look into the health effects associated with the various forms of marijuana delivery into the body.
  • Dedicate funding to public education on the health effects of marijuana. While this is a relatively new area of research, it is key that the public be made aware of any adverse effects that marijuana might have on their health.
  • Regulate the advertising, sponsorship and promotion of marijuana. Products packaging should adhere to the same regulations as tobacco products.


Bottom line:


The Canadian Lung Association strongly cautions all Canadians to avoid smoking marijuana. The Canadian Lung Association is concerned about the potential health risks associated with smoking marijuana.



[i] Donald P. Tashkin "Effects of Marijuana Smoking on the Lung", Annals of the American Thoracic Society, Vol. 10, No. 3 (2013), pp. 239-247.doi: 10.1513/AnnalsATS.201212-127FR

[ii] Hancox, R. J., Shin, H. H., Gray, A. R., Poulton, R., & Sears, M. R. (2015). Effects of quitting cannabis on respiratory symptoms. European Respiratory Journal, 46(1), 80–87.

[iii] Pletcher, M. J., Vittinghoff, E., Kalhan, R., Richman, J. and others. (2012). Association between marijuana exposure and pulmonary function over 20 years. JAMA. 307: 173-18

[iv] Tan WC, Lo C, Jong A, Xing L, Fitzgerald MJ, Vollmer WM, Buist SA, Sin DD; Vancouver Burden of Obstructive Lung Disease (BOLD) Research Group. Marijuana and chronic obstructive lung disease: a population-based study. CMAJ 2009;180:814-20.

[v] Moir D, Rickert WS, Levasseur G, et al. A comparison of mainstream and sidestream marijuana and tobacco cigarette smoke produced under two machine smoking conditions. Chem Res Toxicol. 2008;21(2):494-502. doi:10.1021/tx700275p.