Population-level estimates of workplace exposure to secondhand smoke in Canada

Secondhand smoke (SHS) is a known lung carcinogen that is also associated with cardiovascular disease and premature death. An important source of exposure to SHS is the workplace. In the past, efforts have been made to reduce workplace SHS exposure across Canada, with corresponding benefits to public health. This study estimated the number of workers exposed to SHS in Canada in 2006 and 2016 and their level of exposure.

The proportion of workers exposed to SHS and the proportion of workers reporting specific workplace smoking restrictions by occupation and province, acquired from the 2007-2009 and 2010-2012 Canadian Tobacco Use Monitoring Surveys, were applied to 2006 and 2016 Canadian census data to estimate population-level exposure. Workers were assigned to exposure levels (possible, moderate, high) using workplace smoking restrictions. Only moderately and highly exposed workers were considered exposed.

The number of exposed workers decreased by 20% from 520,000 in 2006 to 418,000 in 2016. Workers were equally split between moderate and high exposure groups. Trades, transport and equipment operators, and workers in primary industry had the highest rates of overall exposure. The proportion of workers exposed varied by province, with the lowest rates in Ontario (approximately 2% in both years), and the highest in Saskatchewan in 2006 (6%) and Newfoundland in 2016 (4%).

Workplace SHS exposure persists. The findings can help prioritize high-risk groups for interventions and inform studies of the burden of occupational disease. Further characterization of exposure is needed to better inform enforcement and prevention.