Second-hand smoke

There is no safe level of exposure to tobacco smoke. Even brief exposure can be harmful to health.^{Footnote 1Footnote 2Footnote 3}

On this page

• Second-hand smoke
• Health risks of second-hand smoke
• Second-hand smoke is particularly dangerous in enclosed spaces
• How to avoid exposure to second-hand smoke and reduce your health risks
• You have the right to be smoke-free

Second-hand smoke

Second-hand smoke refers to both the smoke coming directly from the burning end of a tobacco product and the smoke exhaled by a person who is smoking. In both situations, the smoke from the lit end of a tobacco product such as a cigarette, pipe, cigar, or hookah increases your risk of negative health effects. It contains a composition of more than 7,000 chemicals, of which hundreds are toxic and more than 70 are known to cause cancer.^{Footnote 1Footnote 2Footnote 4Footnote 5Footnote 6}

The formation of most of these chemicals, including carbon monoxide, benzene, formaldehyde and hydrogen cyanide, occurs during the combustion process in every smoked tobacco product. Other substances, such as lead, nitrosamines and nicotine, occur naturally in the tobacco leaf and are released as the tobacco burns.

Most of the smoke from a lit cigarette is not inhaled by the person who smokes. It fills the air around them, as the cigarette continues to burn. This poses a risk to everyone's health in the area. If you do smoke, avoid smoking around others, especially children, pregnant people and people with breathing problems.

Health risks of second-hand smoke

Every year in Canada, second-hand smoke causes nearly 1000 deaths from lung cancer and heart disease in non-smokers. Exposure to second-hand smoke hurts everyone. But pregnant people and their babies, infants and children are particularly at risk to suffer serious health impacts.

Learn more about tobacco smoke and pregnancy and the health impacts for infants and children.

Even healthy adults who never smoked are at risk for health problems if they breathe second-hand smoke. Second-hand smoke increases their risk of:

• heart problems
• lung cancer
• chronic obstructive pulmonary disease
• breathing problems (like asthma)
• excessive coughing
• nasal and chest infections

For more information, visit our Health effects of smoking and second-hand smoke page

For information on cannabis second-hand smoke visit Cannabis in Canada: Get the facts

Second-hand smoke is particularly dangerous in enclosed spaces

Smoking in enclosed spaces (indoors - like in a home - or car) increases the risks to your health, because the level of second-hand smoke is higher in enclosed spaces. Tobacco smoke toxins remain in a room long after the original exposure has occurred.

Cancer causing chemicals and toxins in second-hand smoke cannot be completely eliminated by:

• opening windows
• using a fan, an air purifier or air freshener
• separating smoking and non-smoking sections

These harmful toxins can also cling to different materials, such as:

• rugs
• curtains
• clothing
• food
• furniture

How to avoid second-hand smoke and reduce your health risks

The only way to protect yourself from second-hand smoke is to avoid exposure. There is no safe level of exposure to tobacco smoke. Ways to avoid tobacco smoke, including second-hand smoke include:

• quitting smoking
• helping someone quit
• making your home and car smoke-free
  • avoiding indoor smoking can lower your own cigarette use and increase your chances of successfully quitting
• if you live in a multi-unit dwelling, find out how to make your home smoke-free in a multi-unit residence
• if you are not ready to quit smoking:
  • only smoke in areas where others will not be exposed to your smoke
  • when smoking outside a building, make sure you are several meters away from entrances, vents and windows
  • use a designated container for cigarette ashes and filters (butts)

You have the right to be smoke-free

There are laws and regulations that protect your right to smoke-free air. Smoke-free laws are in place at the federal, provincial, territorial and municipal levels to protect your health. These laws ban smoking in places such as:

• federal buildings
• workplaces
• schools
• bars, casinos, restaurants and patios
• planes, trains, public ferries and buses (including shelters)
• public beaches
• city-owned property (like parks and playgrounds)

For more information on regulating smoking in federal workplaces and other public places under federal control, please visit Regulating tobacco and vaping products.

For more information on policies in most other public places and in private places, check with your provincial or territorial Ministry of Health as well as your municipal government.

Related links

• Quit with confidence: deciding to quit
• Second-hand aerosol vs second-hand smoke
• Tobacco: behind the smoke (infographic)
• Tobacco: behind the smoke (video)
• Health-related messages for all tobacco product packaging: Health information messages