Second-hand smoking
Breathing in other people’s smoke is called second-hand smoking (SHS). It is also known as passive or involuntary smoking.
Second-hand smoking is harmful because:
- it contains over 4,000 chemicals that can cause asthma, meningitis, bronchitis, pneumonia, heart disease, cancer and sudden infant death syndrome (SIDS)
- 80% of second-hand smoke is invisible and has no smell—so even if you think you're being careful, people around you can still breathe it in
- it’s linked to around 2,700 deaths each year in people aged 20 to 63, and around 8,000 deaths in people aged 65 and over
- children who live with smokers are twice as likely to start smoking themselves
- pregnant women and people with existing health conditions are especially at risk
How to protect against second-hand smoke
The only way to protect your friends and family from second-hand smoke is to keep the environment around them smoke free.
The best way to do that is to quit smoking completely.
If you're not ready to quit, make every effort to keep your cigarette smoke away from other people. You should:
- always smoke outside
- ask your visitors to smoke outside
- not smoke in the car, or allow anyone else to
You can read more about second-hand smoking in Action on Smoking and Health’s information document on SHS.
Page last updated: 20 October 2025
