Health effects of smoking and second-hand smoke

Tobacco use is the leading preventable cause of premature death and diseases in Canada. It plays a role in causing disease and other serious health outcomes, including cancer, respiratory ailments, and heart disease, not only for the person who smokes, but for anyone exposed to second-hand smoke. Second-hand smoke comes from burning tobacco products and from exhaled tobacco smoke. Second-hand smoke creates serious health risks for you and your family. Avoid these risks by keeping your home and car smoke-free.

It's never too late to quit smoking. People of all ages experience immediate and long-term health benefits from quitting smoking. To learn more, visit the Benefits of quitting smoking page.

On this page

What are the health risks of second-hand smoke?

There is no safe level of exposure to tobacco smoke. Second-hand smoke contains the same chemicals that are inhaled by the person smoking (including nicotine). Out of the over 7,000 chemicals, more than 70 can cause cancer. Second-hand smoke exposure, even for a short period, hurts everyone.

Pregnant people and their babies

Smoking tobacco during pregnancy results in serious risks for both the person who smokes and their baby. Smoking cigarettes during pregnancy increases the risk of complications, such as low birth weight, stillbirths, decreased fetal growth, premature births, placental abruption and sudden infant death syndrome (SIDS). Pregnant people exposed to second-hand smoke are also at a higher risk for problems with childbirth.

A fetus is particularly vulnerable to second-hand smoke. Second-hand smoke chemicals can reach them through the placenta. Exposing them to second-hand smoke can increase their risk of low birth weight and delayed growth. It can also put them at risk of developing health problems during childhood, such as leukemia, lymphomas and brain tumors.

For more information, please visit Exposure to second-hand smoke exposure during pregnancy.

Infants and children

Second-hand smoke is especially dangerous for babies and children. Their lungs are still developing and are not as strong as those of adults.

Increased health risks from second-hand smoke include:


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:

Every year in Canada, second-hand smoke causes nearly 1000 deaths from lung cancer and heart disease in non-smokers.

If you do smoke, avoid smoking around others, especially children, pregnant people and people with breathing problems.

How can I avoid second-hand smoke and reduce my health risks?

Cleaning or filtering the air, increased ventilation or separated areas (non-smoking sections) cannot completely eliminate exposure to second-hand smoke nor the health risks associated with this exposure.End Note i

The only solution to protect non-smokers is to eliminate smoking in all enclosed spaces such as restaurants, homes (including multi-unit dwellings), workplaces and automobiles. Keep second-hand smoke away from others by following these safety measures:

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 bans smoking in places such as:

Check with your provincial or territorial Ministry of Health as well as your municipal government to find out which policies are in effect where you live.

For more information, you can refer to the Non-smokers' Health Act. This Act regulates smoking in federal workplaces and other public places under federal control.

Related links

End Notes

End Note i

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. Available from:

Return to End Note i referrer

Page details

Date modified: