Passive smoking

What is passive smoking?

Passive smoking means breathing in other people's tobacco smoke. This smoke is often called environmental tobacco smoke (ETS) or second-hand smoke (SHS). It is made up of "sidestream" and "mainstream" smoke. Sidestream smoke comes from the burning tip of the cigarette and is the major component of SHS. Mainstream smoke is the smoke that is exhaled by the smoker.

What's in tobacco smoke?

Tobacco smoke contains over 4000 chemicals either in the form of particles or gases. Particles include tar, nicotine, benzene and benzo(a)pyrene. Some of these chemicals have marked irritant properties and 60 of them are known or suspected carcinogens (cancer causing substances). The gases include carbon monoxide, ammonia, dimethylnitrosamine, formaldeyhde, hydrogen cyanide and acrolein. Many of the chemicals and gases are more concentrated in sidestream than in mainstream smoke.

Health risks from passive smoking

Environmental tobaco smoke has been labelled "carcinogenic to humans" by the WHO's International Agency for Research on Cancer (IARC).1 It has also been labelled a "class A human carcinogen" by the US Environmental Protection Agency,2 along with asbestos, arsenic, benzene and radon gas. In order to help minimise the exposure of Scots to second-hand smoke, the Scottish Executive passed the Smoking, Health and Social Care Act (Scotland) Act 2005.  The Act became law at 6am on Sunday 26th March 2006 and prohibits smoking in most enclosed public places and workplaces.

Health risks from passive smoking at work

• SHS increases the risk of an acute coronary heart disease event by 25-35%.
• Exposure to passive smoking increases the risk of lung cancer by between 20- 30%.
• SHS increases the risk of stroke by 82%.
• A recent study based on subjects from Glasgow showed that those exposed to SHS in the workplace suffered a decrease in lung function, with those exposed to the highest levels of SHS losing over a quarter of a litre of lung function as a result.

Those working on low incomes, or in small businesses, and in the hospitality industry are at greatest risk.

• A US study showed hospitality workers had a 50% higher risk of lung cancer than the general population - after controlling for active smoking

Ventilation is a short-term measure that can increase comfort but cannot be considered as an adequate solution to the health risks of second-hand smoke. There is no safe level of exposure to second-hand smoke, and ventilation systems do not reduce the significant health risks associated with passive smoking.  Scotland's smoke-free legislation will help minimise people's exposure to second-hand smoke.

Action in other countries

• For an overview of smoke-free legislation in other countries, please view ASH Scotland's Briefing on smoke-free legislation around the world.
• Successful legislation has already had an impact in California, Massachusetts, New York, parts of Australia and elsewhere.

More information is available in the hot topics section of our website.