Passive smoking

Passive smoking is the inhalation of tobacco smoke, called passive smoke, secondhand smoke (SHS) or environmental tobacco smoke (ETS), by individuals other than the active smoker. It occurs when tobacco smoke diffuses into the surrounding atmosphere as an aerosol pollutant, which leads to its inhalation by nearby bystanders within the same environment. Exposure to secondhand tobacco smoke causes many of the same health effects caused by active smoking,^[1][2] although at a lower prevalence due to the reduced concentration of smoke that enters the airway.

According to a WHO report published in 2023, more than 1.3 million deaths are attributed to passive smoking worldwide every year.^[3] The health risks of secondhand smoke are a matter of scientific consensus,^[4][5][6] and have been a major motivation for smoking bans in workplaces and indoor venues, including restaurants, bars and night clubs, as well as some open public spaces.^[7]

Concerns around secondhand smoke have played a central role in the debate over the harms and regulation of tobacco products. Since the early 1970s, the tobacco industry has viewed public concern over secondhand smoke as a serious threat to its business interests.^[8] Despite the industry's awareness of the harms of secondhand smoke as early as the 1980s, the tobacco industry coordinated a scientific controversy with the purpose of stopping regulation of their products.^{[4]: 1242 [6]}