Also known as involuntary smoking, it happens when you are in the same room, house, car or public place as smokers. The smoke contains toxic substances that can damage the health of anyone who breathes it in, especially babies, children and pregnant women.

Where does second-hand smoke come from?

The smoke comes from:

• the burning ends of cigarettes, pipes or other tobacco products; or
• the lungs, noses or mouths of smokers

Does passive vaping create second-hand smoke?

Breathing in vapours from other people’s e-cigarettes or ‘vapes’ is not the same as passive smoking because no cigarette smoke is involved. However, passive vaping can still harm your health because the vapour from e-cigarettes contains nicotine and other toxic substances, including formaldehyde and nitrosamines, which are linked to cancer and lung disease.

What does passive smoking do?

Passive smoking can increase the risk of illness and premature death in babies, children and adults. Tobacco smoke contains hundreds of toxic chemicals, including about 70 substances that can cause cancer. Even small amounts are harmful.

In babies, passive smoking can cause sudden infant death syndrome, probably because chemicals from the smoke affect the brain and interfere with breathing.

Babies and children exposed to passive smoking may also get other illnesses such as:

• certain childhood cancers
• asthma
• acute infections of the lungs and respiratory system
• ear problems

In adults, second-hand smoke can increase the risk of:

• lung cancer
• coronary heart disease
• stroke
• wheezing, shortness of breath and asthma.

In pregnant women, the effects of passive smoking can include:

• impeding the lung development of the unborn babies
• premature birth
• low birth weight

Who is at greatest risk?

Babies and children are at risk from passive smoking because they cannot control or move out of their environment.

People who live in overcrowded conditions with smokers are also at risk.

How to reduce exposure to passive smoking

The only way to totally protect people from second-hand smoke is not to allow smoking in homes and other indoor spaces.

In Australia, state and territory laws ban smoking in public indoor spaces such as nursing homes, schools, offices, shopping malls, buses and trains. Some states ban smoking in cars if any children under the age of 16 or 18 years old are present.

Smoke-free and tobacco control laws vary from state to state, so check your state'slegislation to ban smoking in public spaces for the latest information.

There is also national legislation banning smoking on domestic and international flights, as well as interstate buses. The law allows airports to put up no smoking signs.

To protect yourself and your children:

• insist your home is smoke-free
• ask your partner, family or friends to smoke outside — it is not enough for them to go to another room, since smoke can move about the house
• encourage the smoker to quit — even the smoke particles on clothes can harm people

Ask colleagues or family member using e-cigarettes or vapes to ‘smoke’ them outside.

What can I do about second-hand smoke if I am a smoker?

If you are a smoker, consider quitting. If you’d like help and support, go to the Quitline or call 13 78 48.

To protect non-smokers from your smoke:

• obey the law in smoke-free public spaces
• at home, smoke outdoors, far away from other people, especially babies and children
• wear a smoking jacket or shirt and take it off before coming indoors
• don’t smoke near playgrounds or other places where there are children and pregnant women
• stay downwind of people in parks or picnic spots
• respect other people’s right to a smoke-free environment

If you are breastfeeding and still smoking, time your smoking so it happens straight after you have fed your baby. The nicotine levels in your breast milk halve within about 90 minutes after your last cigarette.

Find out more from the Australian Breastfeeding Association about breastfeeding and smoking and how to protect your baby.