Secondhand smoke is the smoke exhaled from the lungs of smokers and the smoke that comes from the burning end of a cigarette, cigar or pipe. There are an estimated 150,000 to 300,000 cases every year of infections, such as bronchitis and pneumonia in infants and children under 18 months of age who breathe secondhand smoke. Secondhand smoke contains more than 4,000 substances, more than 40 of which are known to cause cancer in humans or animals and many of which are strong irritants. Secondhand smoke causes about 3,000 deaths each year from lung cancer in people who don't smoke.
Secondhand smoke causes irritation of the eyes, nose, and throat.
Secondhand smoke can also irritate the lungs, leading to coughing, excessive phlegm, and chest discomfort. Secondhand smoke has been linked with the onset of chest pains and may affect the heart, according to some studies. Children who breathe secondhand smoke are more likely to suffer from pneumonia, bronchitis, and other lung diseases. Children who breathe secondhand smoke have more ear infections. Children who breathe secondhand smoke are more likely to develop asthma.