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Tobacco smoke and risks to non-smokers

Smoking is dangerous not only to the smokers themselves but also to non-smokers, so-called passive smokers who inhale their smoke second-hand. In the indoor environment, pollutants and particles from smoke are also adsorbed onto surfaces and contaminate dust and other materials and continue to have harmful health effects for many hours. Many European countries have recognised the crucial importance of protecting people’s health in public places. In Italy, for example, the 2003 law banning smoking includes all public spaces. Tobacco smoke contains a lethal mixture of thousands of chemicals. Many are toxic, and some, including formaldehydebenzene and vinyl chloride, are known to be carcinogenic. As the harmful chemicals in smoke linger in the indoor environment for long periods of time, the only way to protect non-smokers is to create and maintain a smoke-free environment.

Exposure to tobacco smoke may take three different forms:

  • Primary smoke is the smoke that is inhaled by smokers directly into their lungs.
  • Mainstream smoke is the smoke exhaled by smokers through their mouth and nose.
  • Side-stream smoke is the smoke from the lit end of a cigarette, pipe or cigar.

Other people’s smoke

Second-hand smoke, also known as environmental tobacco smoke, is a mixture of both mainstream and side-stream smoke, which have different properties. Side-stream smoke contains higher concentrations of carcinogens and is more toxic than mainstream smoke. It also comprises smaller particles than mainstream smoke, which make their way into the lungs.

When non-smokers are exposed to second-hand smoke they become passive or involuntary smokers. Non-smokers who breathe in second-hand smoke take in nicotine and toxic chemicals by the same route as smokers. In terms of health risks, the only difference between smokers and non-smokers is the amount of smoke and nicotine that are inhaled. Children exposed to second-hand smoke have an increased risk of infection (four times higher than an adult). The more second-hand smoke you breathe, the more of these harmful chemicals enter your body.

Lingering danger

Every individual present in a room containing environmental tobacco smoke, whether they are smokers or non-smokers, will be exposed to a similar level of chemicals, because nearly 85 percent of environmental tobacco smoke in a room comes from side-stream smoke. Smokers are also exposed to mainstream smoke, although this exposure is limited to the time spent actually smoking the cigarette. By contrast, exposure to environmental tobacco smoke remains constant during the entire time spent in the room.

Recent research has demonstrated that tobacco smoke contamination lingers even after a cigarette has been extinguished — a phenomenon they refer to as third-hand smoke. Some smoke components in the air become attached to other materials, mainly textiles and hair. Third-hand smoke is created as a result of chemical residues that are deposited on furniture, upholstery and clothes. These compounds react with other chemical pollutants present in the indoor air coming from other indoor sources and generate other toxic substances. Chemicals from smoke that are adsorbed onto clothes, curtains or carpets may be further released into the indoor environment, are not eliminated by ventilation, and may need to be removed by special cleaning. Just think how your coat smells after hanging in a smoke-filled environment. Little is known at present about which chemicals contribute most to third-hand smoke, or about the extent of the additional health risk posed by third-hand smoke. However, the best preventive approach is to ensure a smoke-free indoor environment. Infants and children who are regularly exposed to second-hand smoke may suffer allergic reactions to the chemicals, are at greater risk of developing frequent colds and respiratory infections (including bronchitis and pneumonia), and may exhibit slow or incomplete lung growth and development or experience asthma and chronic coughs and chronic or recurrent ear infections.