By Raising Children Network

Tobacco smoke contains over 4000 chemicals. Over 60 of these are known to cause cancer in humans.

Second-hand smoke is the smoke you breathe in from other people’s cigarettes, cigars or pipes. It can cause serious health problems for your child. Breathing in second-hand smoke is sometimes known as passive smoking.

Second-hand smoke is made up of ‘mainstream’ smoke, which the smoker breathes out, and ‘sidestream’ smoke, which drifts from the end of a burning cigarette. Breathing in second-hand smoke is sometimes known as passive smoking. Children most commonly come into contact with second-hand smoke when their parents, family and friends smoke.

Third-hand smoke

Third-hand smoke is the toxins that land and stay on nearly every surface in the area where someone has been smoking, including on clothes, in hair, on furniture and on flooring. This means babies and children are still exposed to the harmful chemicals in cigarettes even after adults have finished their cigarettes.


Second-hand and third-hand smoke are especially dangerous for babies and children. This is because babies and children have smaller airways and less mature immune systems than grown-ups. Their smaller airways mean they breathe faster, so they breathe in a lot more of a cigarette’s harmful chemicals than an adult would in the same time.

Babies and children are also closer to the floor and often put their hands and toys into their mouths. This means they might swallow or breathe in the toxins from third-hand smoke.

Health Risks

Children exposed to second-hand smoke are at an increased risk of premature death and disease and are more likely to have thickening, irritation and inflammation of their airways.

Second-hand smoke can impair a baby’s breathing and heart rate, which can put the baby at a higher risk of sudden unexpected death in infancy (SUDI including SIDs and fatal sleeping accidents). If parents smoke during pregnancy and after their baby is born, their baby’s SIDS risk increases. The more second-hand smoke a baby is exposed to, the higher the risk of SIDS.

If children are exposed to second-hand smoke, they are more likely to develop a range of lung and other health problems, including:


  • asthma
  • bronchiolitis
  • bronchitis
  • childhood cancers, including leukaemia
  • croup
  • ear infections
  • impaired sense of smell
  • meningitis
  • meningococcal disease
  • pneumonia
  • tonsillitis


Exposure to second-hand smoke can increase the likelihood of behaviour problems and learning difficulties for children.

And exposure to second-hand smoke and third-hand smoke can affect a child’s developing brain because the brain is very sensitive to even very small amounts of toxins.

Protecting Your Child

The most important way to protect your child from second-hand smoke is to quit smoking. This reduces your child’s exposure to second-hand and third-hand smoke. It also gives your child a positive non-smoking role model. If you are not quite ready to quit, or someone else in your home is the one smoking, there are still things you can do to reduce your child’s exposure to the smoke.

  • One of the most important things you can do is to make sure no-one smokes near your child in your house or car. This means you’ll have to smoke away from your child, and that you’ll need to ask other family members, friends and visitors to do the same. Also make sure no-one ever smokes in an enclosed area near your child.
  • You might need to explain to friends and family that simply blowing smoke away from your child doesn’t protect your child from the harmful effects of smoke.


  • When visiting friends, or leaving children in the care of someone else, try to make sure the environment is free of smoke.
  • Never smoke in a car that carries children. Opening the car window is not enough to stop smoke affecting children.


  • The only way to protect children from third-hand smoke is to have a smoke-free home and car. You cannot get rid of third-hand smoke by airing out rooms, opening windows, using fans or air conditioners, or confining smoking to certain areas of a home.