Second-Hand Smoke: Let's Clear the Air

Frequently asked questions about second-hand smoke.

What is second-hand smoking?
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. Second-hand smoke is produced during the burning and smoking of tobacco products. It results from the "sidestream" smoke which is emitted from the burning tip of a cigarette and the "mainstream" smoke that has been inhaled and then exhaled by the smoker.

What is found in second-hand smoke?
Second-hand smoke is a complex combination of over 4000 chemicals in the form of particles and gases. It includes irritants and systemic toxicants 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 are reproductive toxicants such as nicotine, cadmium and carbon monoxide. Second-hand smoke is also an important indoor air pollutant. The United States Environmental Protection Agency has classified second-hand smoke as a "class A" carcinogen for which there is no safe level of exposure.

Does second-hand smoke affect the health of non-smokers?
Yes. There is substantial scientific evidence that second-hand smoke is a serious health threat. Non-smokers who breathe second-hand smoke suffer many of the diseases of active smoking. Heart disease mortality 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, 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 causes reductions in fetal growth, and there is also evidence that postnatal exposure of infants to second-hand smoke contributes to the risk of sudden infant death syndrome (SIDS).

Tobacco smoke is also an important source of indoor air pollution, causing such immediate effects as eye and nasal irritation, headache, sore throat, dizziness, nausea, cough, and respiratory problems.

How big a problem is second-hand smoke?
It is a ubiquitous problem because people from all cultures and countries are exposed to second-hand smoke. This exposure occurs under daily-life conditions: in homes, at work, on public transport, in restaurants, in bars - literally everywhere people go.

Surveys conducted in countries around the world confirm widespread exposure. One survey estimated that 79 percent of Europeans over age 15 were exposed to second-hand smoke. Recent data from South Africa shows that 64 percent of children below age five in Soweto live with at least one smoker in the house. The Cancer Society of New Zealand reports that that second-hand smoke is the third largest killer in the country, after active smoking and alcohol use.

Source: World Health Organisation website
http://www.who.int/health_topics/tobacco/en/

Page currency, Latest update: 14 February, 2006