02 March 2006

Frequently asked questions about second-hand smoke

Find out what second-hand smoke is, what is in it and how it affects you.

Frequently asked questions about second-hand smoke (by the World Health Organisation)
  • What is second-hand smoke?
  • Second-hand smoke results from the “sidestream” smoke that comes from the burning tip of a cigarette and the “mainstream” smoke that is exhaled by the smoker. Second-hand smoking, passive smoking, involuntary smoking or exposure to environmental tobacco smoke (ETS) all refer to the phenomena of breathing other people’s smoke.

  • What's in second-hand smoke?
  • Second-hand smoke is the smoke that individuals breathe when they are located in the same air space as smokers.

    Second-hand smoke is a mixture of exhaled mainstream smoke from the tobacco user, sidestream smoke emitted from the smoldering tobacco between puffs, contaminants emitted into the air during the puff, and contaminants that diffuse through the cigarette paper and mouth end between puffs.

    It is a complex combination of over 4000 chemicals in the form of particles and gases. It includes irritants and systemic poisons such as hydrogen cyanide, sulphur dioxide, carbon monoxide, ammonia, and formaldehyde.

    It also contains carcinogens and mutagens such as arsenic, chromium, nitrosamines, and benzo(a)pyrene.

    Many of the chemicals, such as nicotine, cadmium and carbon monoxide, damage reproductive processes.

  • How does second-hand smoke affect health?
  • Non-smokers who breathe second-hand smoke suffer many of the same diseases as regular smokers. Heart disease deaths as well as lung and nasal sinus cancers have been causally associated with second-hand smoke exposure.

    Second-hand smoke also causes a wide variety of adverse health effects in children including bronchitis and pneumonia, development and exacerbation of asthma, middle ear infections, and “glue ear”, which is the most common cause of deafness in children.

    Exposure of non-smoking women to second-hand smoke during pregnancy reduces foetal growth, and postnatal exposure of infants to second-hand smoke greatly increases the risk of sudden infant death syndrome (SIDS).

    Tobacco smoke also causes immediate effects such as eye and nasal irritation, headache, sore throat, dizziness, nausea, cough, and respiratory problems.

  • Are well-ventilated non-smoking sections the answer?
  • No. Although good ventilation can help reduce the irritability of smoke, it does not eliminate its poisonous components. When smoking sections share ventilation with non-smoking areas, the smoke is dispersed everywhere.

    Smoking sections only help protect non-smokers when they are completely enclosed, have a separate ventilation system that goes directly outdoors without re-circulating air in the building, and when employees are not required to pass through them.

  • How can we protect people from second-hand smoke?
  • Governments can regulate and legislate smoking bans in public places, educate people about the dangers of second-hand smoke, and provide support for those who wish to quit smoking.

    Employers can initiate and enforce smoking bans in workplaces.

    Parents can stop smoking in the house and car, particularly around children, and ask others to do the same. They can also ensure that their children's day-care, school and after-school programs are smoke-free.

    Individuals can let their family, friends and co-workers know that they do mind if they smoke near them.


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