Secondhand smoke Secondhand smoke Cigarette smoking is harmful, not only to the smoker, but to those around him or her who are forced to breathe in the secondary smoke.
Most lung cancer is caused by cigarette smoking.
Exposure to other people's tobacco smoke increases the risk of lung cancer among nonsmokers. Scientists have found that nonsmokers who live or work with smokers have a higher lung cancer risk than nonsmokers who do not have this type of exposure to tobacco 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 than the smoke that's directly inhaled by the smoker. While adults can try to avoid being in smokey areas, children and infants are especially vulnerable.