Passive smoking

Passive or involuntary smoking occurs when the exhaled and ambient smoke (otherwise known as environmental or secondhand smoke) from one person's cigarette is inhaled by other people. Passive smoking involves inhaling carcinogens, as well as other toxic components, that are present in secondhand tobacco smoke. Carcinogens that occur in secondhand tobacco smoke include benzene, 1,3-butadiene, benzo[a]pyrene, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, and many others.

It is confirmed that, in adults, secondhand smoke causes lung cancer, nasal sinus cancer, breast cancer in younger women, heart disease, heart attacks, and asthma induction. Secondhand smoke is also known to harm children, infants and reproductive health through acute lower respiratory tract illness, asthma induction and exacerbation, chronic respiratory symptoms, middle ear infection, lower birth weight babies, and Sudden Infant Death Syndrome.

In June 2006, US Surgeon General Richard H. Carmona called the evidence against passive smoke "indisputable" and said "The science is clear: secondhand smoke is not a mere annoyance, but a serious health hazard that causes premature death and disease in children and non-smoking adults.".Passive smoking is one of the key issues that have lead to introduction of smoking bans, particularly in workplaces.

The composition of Environmental tobacco smoke (ETS) is similar to fossil fuel combustion products that contribute to air pollution, and has been shown to be responsible for indoor particulate matter (PM) levels far exceeding official outdoor limits.