Secondhand smoke, also known as environmental tobacco smoke (ETS), is a mixture of the smoke given off by the burning end of a cigarette, pipe or cigar and the smoke exhaled from the lungs of smokers. When a cigarette is smoked, about half of the smoke is inhaled / exhaled (mainstream smoke) by the smoker and the other half floats around in the air, and is also called sidestream smoke.
There are over 4000 chemical compounds in secondhand smoke; 200 of which are known to be poisonous, and upwards of 60 have been identified as carcinogens.
It lingers in the air hours after cigarettes have been extinguished and can cause or exacerbate a wide range of adverse health effects, including cancer, respiratory infections, and asthma.
- Secondhand smoke has been classified by the Environmental Protection Agency (EPA) as a known cause of cancer in humans (Group A carcinogen).
- Secondhand smoke exposure causes disease and premature death in children and adults who do not smoke. Secondhand smoke contains hundreds of chemicals known to be toxic or carcinogenic, including formaldehyde, benzene, vinyl chloride, arsenic ammonia and hydrogen cyanide.
- Secondhand smoke causes approximately 3,400 lung cancer deaths and 22,700-69,600 heart disease deaths in adult nonsmokers in the United States each year.
- Nonsmokers exposed to secondhand smoke at work are at increased risk for adverse health effects. Levels of secondhand smoke in restaurants and bars were found to be 2 to 5 times higher than in residences with smokers and 2 to 6 times higher than in office workplaces.