Second-Hand Smoke

Second-hand smoke causes premature death and disease in children and adults who do not smoke.Footnote 1

Key facts about second-hand smoke exposure

  • In 2012, second-hand smoke was responsible for 993 deaths in Canada.Footnote 2
  • There is no safe level of exposure to second-hand smoke. Even brief exposure can be harmful to health.Footnote 1Footnote 3Footnote 4
  • People who do not smoke but live with someone who smokes have a 30% increased risk of lung cancer, heart disease, and stroke.Footnote 1Footnote 3Footnote 4
  • In 2015, second-hand smoke caused 429 out of 7,112 new lung cancer cases and 131 out of 926 new cervical cancer cases.Footnote 5
  • Second-hand smoke is a major risk factor for sudden infant death syndrome (SIDS).Footnote 1
  • Infants and children exposed to second-hand smoke have a higher risk of respiratory illnesses and ear infections. Second-hand smoke exposure can cause more severe asthma attacks in children with asthma.Footnote 1

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What is second-hand smoke?

Second-hand smoke is the smoke that comes from a burning tobacco product and the smoke exhaled by a person who is smoking. Many of the chemicals in tobacco smoke are therefore also found in second-hand smoke.

An estimated 22% of Canadians who do not smoke are exposed to second-hand smoke every day or almost every day.Footnote 6 Children and adolescents have the highest measurable exposure to second-hand smoke among those exposed in the home.Footnote 6

How does second-hand smoke increase health risks?

Second-hand smoke contains more than 70 cancer-causing chemicals, called carcinogens.Footnote 11Exposure to these chemicals through second-hand smoke can contribute to tumour formation in the lungs, resulting in lung cancer.

Second-hand smoke also contributes to the formation of blood clots in blood vessels, contributing to heart disease and stroke.Footnote 1Footnote 4

Maternal smoking during pregnancy and exposure to second-hand smoke after birth can affect infant brain and lung development. Second-hand smoke is also a risk factor in sudden infant death syndrome (SIDS), lower respiratory illnesses, ear infections, and more severe asthma.Footnote 1Footnote 4Footnote 7

How can I protect my family from second-hand smoke?

Cleaning or filtering the indoor air, increased ventilation, or segregated smoking areas do not eliminate exposure to second-hand smoke nor the associated health risks.Footnote 1

Second-hand smoke concentrations in vehicles can be much higher than in other enclosed spaces. Every Canadian province and territory prohibits smoking in vehicles carrying minors; however, 26% of youth were exposed to second-hand smoke in a vehicle in 2016-2017.Footnote 8

The only solution is to eliminate smoking in all enclosed spaces, such as vehicles and homes.

Health benefits of quitting tobacco use at any age

Quitting tobacco use reduces the risk of premature death, improves health, and enhances quality of life.Footnote 9 Quitting at any age is beneficial to one's health.Footnote 9 Even people who have smoked or used tobacco heavily for many years benefit from it.Footnote 9Footnote 10 Quitting is the most important thing someone who smokes can do to improve their health.

Read more about the benefits of quitting smoking.

For help to quit

Free quit counselling, coaching and other services in your province or territory

Find services to quit smoking

Footnotes

Footnote 1

U.S. Department of Health and Human Services. The Health Consequences of Involuntary Exposure to Tobacco Smoke. A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centres for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2006.

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Footnote 2

Dobrescu A, Bhandari A, Sutherland G, Dinh T. The costs of tobacco use in Canada, 2012. The Conference Board of Canada; 2017. https://www.conferenceboard.ca/temp/ca27ce7a-a964-4288-ba37-82322180d648/9185_Costs-Tobacco-Use_RPT.pdf

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Footnote 3

International Agency for Research on Cancer. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Volume 100E: Personal habits and indoor combustions, 2012.

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Footnote 4

U.S. Department of Health and Human Services. The Health Consequences of Smoking—50 Years of Progress: A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2014.

Return to footnote 4 referrer

Footnote 5

Poirier AE, Ruana Y, Grevers X, Walter SD, Villeneuve PJ, Friedenreich CM, et al. Estimates of the current and future burden of cancer attributable to active and passive tobacco smoking in Canada. Preventive Medicine. 2019;122:9–19. https://doi.org/10.1016/j.ypmed.2019.03.015

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Footnote 6

Levesque J, Mischki T. Exposure to tobacco smoke among Canadian nonsmokers based on questionnaire and biomonitoring data. Health Reports. 2021;32(2). https://www.doi.org/10.25318/82-003-x202100200002-eng

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Footnote 7

Zhou S, Rosenthal D, Sherman S, Zelikoff J, Gordon T, Weitzman M. Physical, behavioral, and cognitive effects of prenatal tobacco and postnatal secondhand smoke exposure. Current Problems in Pediatric and Adolescent Health Care. 2014; 44(8):219-241. https://doi.org/10.1016/j.cppeds.2014.03.007

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Footnote 8

Azagba S, Latham K, Shan L. Exposure to secondhand smoke in vehicles among Canadian adolescents: Years after the adoption of smoke-free car laws. Addict Behav Rep. 2019;10:100215. https://dx.doi.org/10.1016%2Fj.abrep.2019.100215.

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Footnote 9

U.S. Department of Health and Human Services. Smoking Cessation: A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2020.

Return to footnote 9 referrer

Footnote 10

U.S. Department of Health and Human Services. The Health Consequences of Smoking. A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2004.

Return to footnote 10 referrer

Footnote 11

International Agency for Research on Cancer. Monographs on the Evaluation of Carcinogenic Risks to Humans. Personal Habits and Indoor Combustions. World Health Organization. Volume 100E:2012. https://publications.iarc.fr/Book-And-Report-Series/Iarc-Monographs-On-The-Identification-Of-Carcinogenic-Hazards-To-Humans/Personal-Habits-And-Indoor-Combustions-2012

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