DEFINITION AND HEALTH EFFECTS
Environmental tobacco smoke consists of "mainstream" smoke exhaled
by an active smoker, and "sidestream" smoke released from the smoldering
end of a cigarette, pipe or cigar. ETS contains more than 3,800 different
chemicals. ETS is qualitatively similar to mainstream smoke, but
contains higher quantities of certain toxins such as ammonia, formaldehyde,
and nitrosamines. It is the main source of particulate matter of less
than 2.5 microns, a size that reaches the lower airways.
In 1998, more than 47.2 million U.S. adults, 24% of the population,
were cigarette smokers (Centers for Disease Control and Prevention, 2000).
Forty-three percent of children aged 2 months to 11 years lived in a home
with a cigarette smoker (Pirkle, Flegal, Bernert, et al., 1996). Young children
may spend a significant amount of their time indoors, in their own
homes, relatives* homes, and child care settings, exposing them to ETS
and making them passive smokers.
EFFECTS ON ADULTS
Adults may be exposed to ETS through a tobacco-using spouse or housemate.
ETS has been classified as a group A human carcinogen, indicating
that there is sufficient scientific evidence supporting a causal relationship
between exposure to ETS and the development of cancer. The U.S.
Environmental Protection Agency has estimated that ETS is responsible
for approximately 3,000 lung cancer deaths per year in nonsmokers in the
United States. In addition, exposure to ETS has been linked with an
increased risk of developing myocardial infarction, reduced pulmonary
function, cough, headache, nasal congestion, and eye irritation.
EFFECTS ON CHILDREN
Children exposed to ETS through maternal smoking may show a number
of negative health effects (American Academy of Pediatrics, 1999) including
(1) Lower respiratory tract infections: These infants are 38% more
likely to be hospitalized for pneumonia in the first year of life than children
whose mothers do not smoke; when both parents smoke, the infants
are twice as likely to be hospitalized than children whose parents do not
smoke. (2) Middle ear effusions: Children of parents who smoke are more
likely to develop middle ear effusion and otitis media. (3) Asthma: These
children are more likely to develop asthma, and those with asthma may
have more severe symptoms and more frequent exacerbations. (4) Sudden
infant death syndrome (SIDS): A growing body of evidence links ETS
exposure to an increased incidence of SIDS, independent of gestational
age or birth weight.
Exposure to ETS before age 10 raises the risk of developing leukemia
and lymphoma in adulthood.