There is clear evidence that breathing in other people’s smoke causes cancer in non-smokers [1–4]. Second-hand smoke, also known as environmental tobacco smoke or passive smoking, exposes people to cancer-causing chemicals .
People who have never smoked have their risk of lung cancer increased by around a quarter if they have a spouse who smokes [1,5]. The risk increases the more second-hand smoke they’re exposed to, people exposed to the highest levels can have their risk of lung cancer doubled [5,6].
Second-hand smoke can reach high levels in enclosed spaces such as within the home or inside a car [7–11]. Studies have shown that even with open windows, levels can be dangerously high [7,9,11,12].
Second-hand smoke also causes other health problems in non-smokers including heart disease and respiratory diseases including asthma in children [1,4,13]. And it may increase the risk of pharyngeal and laryngeal cancers [3,14].
1. Scientific Committee on Tobacco and Health (SCOTH). Secondhand Smoke: Review of evidence since 1998. 2004.
2. IARC. Monographs on the Evaluation of Carcinogenic Risks to Humans VOLUME 83 Tobacco Smoke and Involuntary Smoking. 2004;83.
3. IARC. Personal Habits and Indoor Combustions, Volume 100 E, A Review of Human Carcinogens. 2012;100.
4. U.S. Surgeon General. How Tobacco Smoke Causes Disease : The Biology and Behavioral Basis for Smoking-Attributable Disease.; 2010.
5. Taylor R, Najafi F, Dobson A. Meta-analysis of studies of passive smoking and lung cancer: effects of study type and continent. Int J Epidemiol. 2007;36(5):1048-1059. doi:10.1093/ije/dym158.
6. Stayner L, Bena J, Sasco AJ, et al. Lung cancer risk and workplace exposure to environmental tobacco smoke. Am J Public Health. 2007;97(3):545-551. doi:10.2105/AJPH.2004.061275.
7. Blackburn C, Spencer N, Bonas S, Coe C, Dolan A, Moy R. Effect of strategies to reduce exposure of infants to environmental tobacco smoke in the home: cross sectional survey. BMJ. 2003;327(7409):257. doi:10.1136/bmj.327.7409.257.
8. Lofroth G. Environmental Tobacco Smoke: Multicomponent Analysis and Room-to-room Distribution in Homes. Tob Control. 1993;2:222-225.
9. Wakefield M, Banham D, Martin J, Ruffin R, McCaul K, Badcock N. Restrictions on smoking at home and urinary cotinine levels among children with asthma. Am J Prev Med. 2000;19(3):188-192. http://www.ncbi.nlm.nih.gov/pubmed/11020596
10. ASH Scotland. Smoking in vehicles : An evidence review. 2013;(April).
11. Semple S, Apsley A, Galea KS, MacCalman L, Friel B, Snelgrove V. Secondhand smoke in cars: assessing children’s potential exposure during typical journey conditions. Tob Control. 2012;21(6):578-583. doi:10.1136/tobaccocontrol-2011-050197.
12. Sendzik T, Fong GT, Travers MJ, Hyland A. An experimental investigation of tobacco smoke pollution in cars. Nicotine Tob Res. 2009;11(6):627-634. doi:10.1093/ntr/ntp019.
13. Tobacco Advisory Group of The Royal College of Physicians. Passive Smoking and Children.; 2010.
14. Cogliano VJ, Baan R, Straif K, et al. Preventable exposures associated with human cancers. J Natl Cancer Inst. 2011;103(24):1827-1839. doi:10.1093/jnci/djr483.