Passive smoking can lead to a buildup of fluid in the middle ear as a result of irritation and swelling of the Eustachian tubes connecting the middle ear and nasal passages. The greater the amount of parental smoking the more frequently children of those parents have respiratory infections. In families where both parents smoke, the children have significantly more respiratory infections. Children exposed to passive smoking have significantly reduced pulmonary functioning and their lung growth is hindered. Since they subsequently fail to reach their optimum lung growth, they are more likely to have pulmonary health problems as adults.
Maternal smoking relates more closely to childhood respiratory infection than paternal smoking.
Children exposed to secondhand smoke are more likely to develop asthma. For those children who already have asthma, exposure to secondhand smoke increases the frequency and strength of a child's asthma attacks. Children exposed to parental smoking are more likely to suffer accidental cigarette burns and hazards from fires set by children playing with matches and butane lighters or parents leaving burning cigarettes unattended. Adults, who as children were exposed to significant levels of secondhand smoke, are more likely to have lung cancer, heart disease and cataracts. Children exposed to parental smoking are more prone to becoming smokers.