© 2005-2012 American Society of Clinical Oncology (ASCO). All rights reserved worldwide.
Secondhand smoke, also known as tobacco smoke pollution or environmental tobacco smoke, is a smoker's exhaled smoke plus the smoke from that person's lit cigarette, cigar, or pipe. It is a known carcinogen (a substance that causes cancer). Each year, about 88 million nonsmoking Americans are exposed to other people's smoke, and nearly half of newly diagnosed lung cancers are attributed to secondhand smoke.
Breathing secondhand smoke is referred to as passive smoking or involuntary smoking. Inhaling another person's smoke is like smoking. Many of the harmful substances in tobacco, including benzopyrene, lead, carbon monoxide, arsenic, ammonia, formaldehyde, and a type of cyanide, stay in the air and go into your lungs and bloodstream. Cigars create larger amounts of secondhand smoke than cigarettes because they contain more tobacco and burn longer.
Secondhand smoke and disease
The U.S Surgeon General estimates that living with a smoker increases the chance of getting lung cancer by 20% to 30%. Although research has not yet proved that secondhand smoke causes cancers other than lung cancer, there is some evidence that exposure to secondhand smoke may raise an adult's risk of breast, nasopharyngeal, and nasal sinus cancers. There is also a possible link in children between secondhand smoke and brain tumors, leukemia, and lymphoma.
Many studies show that secondhand smoke causes a large number of other health problems for people of all ages, such as asthma; heart disease in adults; and colds, ear infections, and pneumonia in children. Pregnant women, older adults, and people with respiratory (breathing) conditions and heart disease are especially at risk for the health effects of secondhand smoke.
Secondhand smoke is also especially unsafe for babies and young kids because their bodies and lungs are still developing. In fact, some researchers suggest that the toxins from smoke that remain in a person's hair and clothes or in carpet and furniture are hazardous to infants and children. Researchers describe this gradual buildup of toxins from secondhand smoke as “thirdhand smoke.” Read how to give your kids a smoke-free childhood.
How to avoid secondhand smoke
When someone smokes indoors, it is not enough to keep the smoke away by opening a window or using a fan. The only way to avoid the risks of secondhand smoke is to not be in an indoor space where smoking occurs.
Here are ways you can protect yourself and your family from secondhand smoke.
- Keep your home and car smoke free.
- If your workplace does not ban smoking, ask for restrictions, such as banning smoking indoors.
- Eat in restaurants that are smoke free. Nonsmoking sections do not protect from secondhand smoke.
- When you travel, stay in smoke-free hotels and rent nonsmoking rental cars.
- When indoors, ask smokers to step outside.
- If you live with a smoker, ask the person to smoke outside.
- If you smoke, quit. Learn more about quitting smoking.
Experts say that the only way to fully protect people from secondhand smoke is to get rid of smoking indoors. Anti-smoking laws have helped reduce the exposure to secondhand smoke and most states have passed laws banning or limiting smoking in public places, including the workplace. Almost half of the states and Washington, D.C., also do not allow smoking in restaurants and bars. Many counties and cities also have passed smoke-free laws. Find out more about your state's smoking laws.
National Cancer Institute: Secondhand Smoke: Questions and Answers