The pre-cancerous cells are replaced. The risk of cancer of the mouth, throat, esophagus, bladder, kidney and pancreas decreases. The risk of coronary heart disease is less than that of a non-smoker. Secondhand smoke 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. This mixture 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 can cause lung cancer in non-smokers.
Passive smoking is estimated by EPA to cause approximately 3,000 lung cancer deaths in non-smokers each year. Secondhand smoke is a serious health risk to children. The developing lungs of young children are also affected by exposure to secondhand smoke. Infants and young children whose parents smoke are among the most seriously affected by exposure to secondhand smoke, being at increased risk of lower respiratory tract infections such as pneumonia and bronchitis. EPA estimates that passive smoking is responsible for between 150,000 and 300,000 lower respiratory tract infections in infants and children under 18 months of age annually, resulting in between 7,500 and 15,000 hospitalizations each year.