It is a well-known fact that cigarette smoking is bad for your health, but breathing the smoke of others can also be harmful. Cigarette smoking is the number one cause of lung cancer, which is the leading cause of cancer deaths in men and women. Passive smoking is when a nonsmoking individual is exposed to second-hand smoke.

The immediate effects of breathing second-hand smoke include an increase in heart rate and blood pressure, and dangerous levels of carbon monoxide in the blood. The smoke from the burning end of a cigarette is filled with hundreds of dangerous chemicals and contains more tar and nicotine then the smoke that is directly inhaled.

Second-hand smoke is also referred to as environmental tobacco smoke (ETS), and is the combination of two forms of smoke from burning tobacco products:

• Sidestream smoke, or smoke that is emitted between the puffs of a burning cigarette, pipe, or cigar, and
• Mainstream smoke, or the smoke that is exhaled by the smoker.

When a cigarette is smoked, about half of the smoke generated is sidestream smoke, which contains essentially the same compounds as those identified in the mainstream smoke inhaled by the smoker. Some of the chemicals in environmental tobacco smoke include substances that irritate the lining of the lung and other tissues, carcinogens (cancer-causing compounds), mutagens (substances that promote genetic changes in the cell), and developmental toxicants (substances that interfere with normal cell development).

Tobacco smoke is known to contain at least 60 carcinogens and six developmental toxicants, including nicotine and carbon monoxide. Nonsmokers who are exposed to second-hand smoke absorb nicotine and other compounds just as smokers do.

Although the smoke to which a nonsmoker is exposed is less concentrated than that inhaled by smokers, research has demonstrated significant health risks associated with second-hand smoke.

Health Effects Associated With Second-hand Smoke

Exposure - In 1986, two landmark reports were published on the association between environmental tobacco smoke exposure and the adverse health effects in nonsmokers: one by the U.S. Surgeon General and the other by the Expert Committee on Passive Smoking, National Academy of Sciences' National Research Council (NAS/NRC).

Both of these reports concluded that:

• Second-hand smoke can cause lung cancer in healthy adult nonsmokers;
• Children of parents who smoke have more respiratory symptoms and acute lower respiratory tract infections, as well as evidence of reduced lung function, than do children of nonsmoking parents; and
• Separating smokers and nonsmokers within the same air space may reduce but does not eliminate a nonsmoker's exposure to environmental tobacco smoke.

In 1992, the U.S. Environmental Protection Agency (EPA) confirmed the above findings in its study on the respiratory health effects of environmental tobacco smoke. In addition, the EPA classified environmental tobacco smoke as a Group A carcinogen--a category reserved only for the most dangerous cancer-causing agents in humans.

The EPA report, a compilation of 30 epidemiological studies that focused on the health risks of nonsmokers with smoking spouses, concluded that there is a strong association between second-hand smoke exposure and lung cancer.

Recent studies and the EPA's report point to a 20% increased risk of lung cancer in nonsmokers due to second-hand smoke. In response to evidence that environmental tobacco smoke causes diseases beyond lung cancer and respiratory problems in children, the California EPA conducted a comprehensive assessment of the range of health effects connected with environmental tobacco smoke exposure.

Second-hand Smoke and Children

Children are exposed to second-hand smoke are at higher risk of getting sick because their lungs are still developing and are more easily damaged by second-hand smoke. Children also inhale more air pollutants for their size than adults because they breathe faster than adults.

For children, exposure to even small amounts of second-hand smoke can aggravate their asthma. It is also linked to higher rates of pneumonia, bronchitis, colds, ear infections and sore throats. Many of these children will require ongoing medical attention and hospitalization as a result of exposure to second-hand smoke.

Tobacco smoke puts babies at risk of respiratory infection and also increases the risk of dying from Sudden Infant Death Syndrome (SIDS). A baby exposed to second-hand smoke, or whose mother smoked before or after birth, is at higher risk for SIDS. Don't let other people, like friends and babysitters smoke around your baby.

If you smoke and are concerned of the dangers of second-hand smoke on your friends, family or unborn child, please visit the Quitting Smoking Resource Center for help and guidance on breaking the habit.