Second-hand smoke

Second-hand smoke refers to smoke from a person’s cigarette, pipe or cigar. It is also known as passive smoke, environmental smoke and involuntary smoke.

There are two main types:

  • side-stream smoke — smoke released from the tip of the cigarette
  • mainstream smoke — smoke exhaled by the smoker

Effects of second-hand smoke on adults

Second-hand smoke contains more than 7000 chemicals, with 69 known to cause cancer.

There is no safe level of exposure to second-hand smoke. It can even be more toxic than the smoke inhaled directly from a cigarette, as lower temperatures allow more toxins to be present. Evidence suggests that side-stream smoke may become more harmful as it changes from fresh to stale.

Second-hand smoke causes immediate adverse effects on the cardiovascular system, which have short-term and long-term impacts.

Short-term impacts Long-term impacts
  • sore throat
  • itchy eyes
  • coughing
  • headaches
  • nasal irritation
  • shortness of breath
  • lung and other cancers
  • coronary heart disease
  • chronic obstructive pulmonary disease
  • stroke
  • respiratory issues such as asthma
  • poorer general health outcomes
  • premature death

Evidence pooled from numerous studies indicates a 20 to 30 percent increase in the risk of lung cancer from second-hand smoke exposure associated with living with someone who smokes.

Effects of second-hand smoke on infants and children

Second-hand smoke has adverse impacts on infants and children.

Children are often at greater risk of exposure because they generally do not control their environment and cannot take action to avoid second-hand smoke.

Because their bodies are developing, infants and young children are especially vulnerable to the harmful effects of second-hand smoke. These include:

  • asthma
  • other chronic respiratory symptoms
  • respiratory tract infections
  • decreased lung function
  • middle ear disease
  • other negative health outcomes.

How to reduce exposure to second-hand smoke

Smoking impacts not only the smoker but also the people around them.

Making the environments where we live, work and play, smoke-free is the most effective way to reduce second-hand smoke exposure.

NSW has comprehensive legislation to protect the community from exposure to second-hand smoke in most indoor areas and public places.

You can take other actions to further reduce exposure:

  1. Make your car and home smoke-free environments.
  2. If you or someone in your family smokes, ask them to change their clothes or have a shower before entering the home.
  3. Try quitting smoking or supporting a family member to quit — call the NSW Quitline or visit our Quit Smoking section.

If you have any questions or would like further information on second-hand smoke, please contact the Tobacco Control Unit.