No amount of secondhand smoke is safe, and opening a window doesn't fix it.
5 min read
Optional. Skip it if it doesn't apply to you.
Opening a window or running a fan does not remove the exposure.
The National Cancer Institute says: "There is no safe level of exposure to secondhand smoke." It advises not allowing smoking in your home and not allowing anyone to smoke in your car, even with the windows down. The Surgeon General's report says separating smokers from nonsmokers, cleaning the air and ventilation can't eliminate exposure.
The EPA, the National Toxicology Program, the Surgeon General and IARC all classify secondhand smoke as a known human carcinogen. NCI estimates it caused more than 7,300 lung cancer deaths a year among adult nonsmokers (a 2005 to 2009 estimate), and says some research suggests it may also increase breast cancer risk in adults, though the evidence is less certain.
A 2015 CDC report estimated that more than 41,000 nonsmoking adults die each year from secondhand smoke exposure, through heart disease and lung cancer, and found that the home is the largest source of exposure for children.
If no one in your household smokes and no one smokes in your car, this lesson is a quick check. If someone does, this is the single most useful thing you can change at home.
7,300+
lung cancer deaths a year among adult nonsmokers (2005 to 2009 estimate)
NCI
41,000+
estimated deaths a year among nonsmoking U.S. adults from secondhand smoke (heart disease and lung cancer), based on earlier data
CDC, Vital Signs, 2015
0
known safe level of exposure
NCI; U.S. Surgeon General
1 in 5
nonsmoking U.S. adults were exposed to secondhand smoke (2015 to 2018)
CDC, 2021
Opening windows or running fans
NCI says this doesn't remove the exposure.
Smoking in a separate room
The Surgeon General's report says separating smokers from nonsmokers doesn't eliminate exposure.
Air cleaners and ventilation
Some air cleaners and ventilation systems can reduce certain pollutants, but they cannot eliminate secondhand smoke exposure. Conventional air cleaners also cannot remove all the harmful gases and particles.
The car with the windows down
NCI advises against smoking in your car even with the windows down.
A rule is easier to keep when it's simple and the same for everyone.
Make it one rule
"No smoking in our home or in my car." Simple and the same for everyone.
Tell people ahead of time
Text guests and family before they visit, not at the door. Offer a spot outside, away from doors and windows.
Handle rides
"I keep my car smoke-free, so we'll take a break before we get in."
Put it in writing if you need to
A small sign by the door can do the talking for you.
Secondhand smoke can travel between apartments and through shared spaces. If smoke is entering your home, write down when it happens and contact your landlord or property manager about the building's smoke-free policies.
The national quitline, 1-800-QUIT-NOW, connects callers with free support in their state. Offer to help find it instead of pushing.
Myth
A fan or an open window handles it.
What research says
NCI says opening windows or running fans doesn't remove the exposure.
NCI
Myth
A little exposure is harmless.
What research says
NCI states there is no safe level of exposure to secondhand smoke.
NCI; U.S. Surgeon General
Myth
It's only a risk for children.
What research says
A 2015 CDC report estimated that more than 41,000 nonsmoking adults die each year from secondhand smoke exposure.
CDC, 2015
Decide your rule
Home, car, or both. Write it as one clear sentence.
Tell the people who need to know
Text your household, regular guests and anyone who rides with you this week.
Make it easy to follow
Pick the outdoor spot, and keep an ashtray there and away from doors and windows.
Offer help to quit
If someone wants to quit, share 1-800-QUIT-NOW and offer to check in with them.
- National Cancer Institute: Secondhand smoke and cancer fact sheet (last reviewed Dec 4, 2018)
- Centers for Disease Control and Prevention: Vital Signs: Secondhand smoke exposure (MMWR, 2015)
- U.S. Surgeon General: The Health Consequences of Involuntary Exposure to Tobacco Smoke (fact sheet)
If no one smokes in your home or car, mark this one done.