Passive smoking refers to the smoke that non-smokers are breathing in from active smokers. People who spend time around smokers are breathing in the smoke either from the burning end of the active smoker's cigarette or the smoke expelled by the active smoker. This is also called involuntary or secondhand smoking.
Exposure to secondhand smoke can lead to very serious health problems, such as respiratory diseases, heart disease, and lung cancer. Cigarette smoke has more than 400 chemicals in it, and it creates air pollution. Passive smoking is considered a preventable cause of death that has killed thousands of people exposed to cigarette smoke in homes, workplaces, and/or public places.
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Children are often passive smokers and receive health injuries that they would not have had if their parents did not smoke. Even a small amount of secondhand smoke can affect babies, children, and others. Even when smokers who smoke in the home try to do so near an open window, some smoke still remains and affects other people in the house. People who were exposed to secondhand smoke as children have an increased risk of getting cancer later in life, as well as asthma and respiratory infections.
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Smoke from cigarettes is unhealthy for everyone, and while active smokers choose to smoke, passive smokers do not. Exposure to smoke is especially bad for those with asthma, but it is unhealthy for all people as well as animals. People who are exposed often get headaches, sore throats, and eye irritation. Dizziness, coughing, and nausea may also occur.
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Mainstream smoke refers to the smoke that enters the smoker's body and is not exhaled. The smoke that is exhaled differs chemically, since it interacts with the tissues in the smoker's body. Mainstream passive smoking occurs when the non-smoker breathes in smoke exhaled by the smoker. This type of smoke is harmful, but sidestream passive smoking has been shown to be even more harmful.
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Sidestream passive smoking refers to the non-smoker breathing in smoke from the burning end of the smoker's cigarette. Most of the smoke in a room will be of this type, which has a higher concentration of chemicals than that which is exhaled. Cigarette smoke contains chemicals such as carbon monoxide, benzene, and ammonia and many of the chemicals in cigarettes are either irritants or carcinogens.