Passive smoking

Disclaimer: This fact sheet is for education purposes only. Please consult with your doctor or other health professional to make sure this information is right for your child.

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Passive smoking is breathing in smoke from other people’s cigarettes, cigars or pipes. Smoke that is breathed out by a smoker is called mainstream smoke. The smoke drifting from the burning end of a cigarette is called sidestream smoke. Second Hand Smoke (SHS) also known as Environmental Tobacco Smoke (ETS) is a combination of mainstream and sidestream smoke with each contributing to about half of the smoke generated. Parental smoking is the commonest source of ETS exposure for children.

Sidestream smoke tends to remain in a room longer and contains many cancer causing substances, more than mainstream smoke. As Australians spend a greater part of each day indoors, SHS is a serious but preventable health hazard. Children in particular are at risk of harmful effects from passive smoking.

What is the health risk for unborn babies?

Smoking during pregnancy is harmful to the developing baby. When a pregnant woman is exposed to tobacco smoke, harmful substances absorbed into the mother’s bloodstream can cross the placenta and affect her unborn baby. The placenta does not filter out the many harmful substances in tobacco smoke. Smoking in pregnancy also reduces blood flow through the placenta, which can reduce the amount of oxygen, and nutrients the baby receives. Exposure to tobacco smoke during pregnancy can significantly increase the risk of miscarriage, stillbirth, prematurity, low birth weight, childhood malformations and sudden infant death syndrome. Further it has harmful effects on the developing lung and immune system resulting in decreased lung function at birth and increased allergic and asthmatic responses in childhood.

What is the health risk for children?

  • Children exposed to SHS are at risk of sudden infant death syndrome and are more likely to develop a range of illnesses including asthma, croup, bronchitis, bronchiolitis, pneumonia and middle ear infections as compared to children living in smoke-free environments. Impaired learning, slower growth and changes in behavior can be linked with children’s exposure to passive smoke.
  • Both asthma and respiratory infections (characterised by wheezing, breathlessness, cough and phlegm) are increased in children who are exposed to SHS especially when parents who smoke. Children of smoking parents are about twice as likely to have symptoms of asthma before they are five years old. Tobacco smoke also triggers asthma attacks and makes a child's asthma more severe than it would otherwise be. Many environmental factors contribute to asthma; passive smoking is one that you can avoid.

What are the main sources of SHS for children?

Parents, family and friends who smoke in enclosed areas such as cars and homes are the main source of SHS for children. The harmful effects on children increase with the number of parents or other household members who smoke. Important to remember that back on 1st July 2009, new laws were introduced into NSW on SHS exposure from smoking in the car. If an adult smokes in a car with a child under 16 years old, this will result in a $250 fine.

Smoking outside, away from your child is better but the smell of the smoke is still on your hair, skin and cloths when you return and may affect your child. Leaving your child inside unattended while smoking outside is also a safety risk as unsupervised children are more at risk of harm from their environment.

What you can do to protect your child?

Quitting smoking is the ultimate goal for parents and carers of young children, but other approaches can also make a difference. Options include choosing not to smoke in the car or home or any other enclosed space where children spend time. When visiting friends or leaving your child in the care of another person, consider whether that environment is smoke–free and encourage friends and family who smoke to consider not smoking around children if possible. Important to remember that opening a window in your home and or car does not eliminate exposure to SHS

Seeking help from people experienced in the difficulties of giving up smoking (Quitline counsellors, doctors or chemists) is also helpful. This is particularly important for women who are pregnant or planning pregnancy so that safe options are recommended and made available to them.

As children from smoking families are more likely to take up smoking themselves, parents who quit smoking provide a positive role model for them.

For more information on how to quit smoking, please visit


  • Passive smoke in any form is harmful to children
  • You can choose not to smoke in front of children, particularly in enclosed areas such as the car and home, and ask others to do the same.
  • There is support available through the Quitline on 131 848 or or a, doctor, asthma educator or chemist.
  • Every child has the right to grow up in a ‘smoke free environment'.
The Children's Hospital at Westmead
Sydney Children's Hospital, Randwick
Hunter New England Kids Health

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