United States
Environmental Protection
Agency
Research
and Development
(RD-689)
Air and
Radiation
(6203 J)
&EPA
January 1993
Respiratory Health
Effects of Passive
Smoking
Fact Sheet
Summary
The U.S. Environmental Protection Agency
(EPA) has published a major assessment of
the respiratory health risks of passive
smoking (Respiratory Health Effects of
Passive Smoking: Lung Cancer and Other
Disorders; EPA/600/6-90/006F). The report
concludes that exposure to environmental
tobacco smoke (ETS) -- commonly known as
secondhand smoke — is responsible for
approximately 3,000 lung cancer deaths each
year in nonsmoking adults and impairs the
respiratory health of hundreds of thousands
of children.
Background
EPA studies of human exposure to air
pollutants indicate that indoor levels of
many pollutants often are significantly
higher than outdoor levels. These levels of
indoor air pollutants are of particular
concern because it is estimated that most
people spend approximately 90 percent of
their time indoors.
In recent years, comparative risk studies
performed by EPA and its Science Advisory
Board have consistently ranked indoor air
pollution among the top five
environmental risks to public health. EPA,
in close cooperation with other federal
agencies and the private sector, has begun a
concerted effort to better understand indoor
air pollution and to reduce peoples'
exposure to air pollutants in offices, homes,
schools and other indoor environments
where people live, work and play.
Tobacco smoking has long been recognized
as a major cause of death and disease,
responsible for an estimated 434,000 deaths
per year in the United States. Tobacco use
is known to cause lung cancer in humans,
and is a major risk factor for heart disease.
In recent years, there has been concern that
non-smokers may also be at risk for some of
these health effects as a result of their
exposure ("passive smoking") to the smoke
exhaled by smokers and smoke given off by
the burning end of cigarettes.
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As part of its effort to address all types of
indoor air pollution, in 1988, EPA's Indoor
Air Division requested that EPA's Office of
Research and Development (ORD)
undertake an assessment of the respiratory
health effects of passive smoking. The
report was prepared by ORD's Office of
Health and Environmental Assessment.
The document has been prepared under the
authority of Title IV of Superfund (The
Radon Gas and Indoor Air Quality Research
Act of 1986), which directs EPA to conduct
research and disseminate information on
all aspects of indoor air quality.
Public and Scientific Reviews
A draft of this assessment was released for
public review in June 1990. In December
1990, EPA's Science Advisory Board, a
committee of independent scientists,
conducted a review of the draft report and
submitted its comments to the EPA
Administrator in April 1991. In its
comments, the SAB's Indoor Air
Quality/Total Human Exposure Committee
concurred with the primary findings of the
report, but made a number of
recommendations for strengthening it.
Incorporating these recommendations, the
Agency again transmitted a new draft to the
SAB in May of 1992 for a second review.
Following a July 1992 meeting, the SAB
panel endorsed the major conclusions of
the report, including its unanimous
endorsement of the classification of
environmental tobacco smoke (ETS) as a
Group A (known human) carcinogen.
EPA also received and reviewed more than
100 comments from the public, and
integrated appropriate revisions into the
final risk assessment.
Major Conclusions
Based on the weight of the available
scientific evidence, EPA has concluded that
the widespread exposure to environmental
tobacco smoke in the U.S. presents a serious
and substantial public health risk.
In adults:
• ETS is a human lung carcinogen,
responsible for approximately 3,000 lung
cancer deaths annually in U.S. nonsmokers.
ETS has been classified as a Group A
carcinogen under EPA's carcinogen
assessment guidelines. This classification is
reserved for those compounds or mixtures
which have been shown to cause cancer in
humans, based on studies in human
populations.
In children:
• ETS exposure increases the risk of lower
respiratory tract infections such as
bronchitis and pneumonia. EPA estimates
that between 150,000 and 300,000 of these
cases annually in infants and young
children up to 18 months of age are
attributable to exposure to ETS. Of these,
between 7,500 and 15,000 will result in
hospitalization.
• ETS exposure increases the prevalence of
fluid in the middle ear, a sign of chronic
middle ear disease.
• ETS exposure in children irritates the
upper respiratory tract and is associated
with a small but significant reduction in
lung function.
• ETS exposure increases the frequency of
episodes and severity of symptoms in
asthmatic children. The report estimates
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that 200,000 to 1,000,000 asthmatic children
have their condition worsened by exposure
to environmental tobacco smoke.
• ETS exposure is a risk factor for new cases
of asthma in children who have not
previously displayed symptoms.
Scope of the Report
In 1986, the National Research Council
(NRC) and the U.S. Surgeon General
independently assessed the health effects of
exposure to ETS. Both of these reports
concluded that ETS can cause lung cancer i n
adult non-smokers and that children of
parents who smoke have increased
frequency of respiratory symptoms and
lower respiratory tract infections. The EPA
scientific assessment builds on these reports
and is based on a thorough review of all of
the studies in the available literature.
Since 1986, the number of studies which
examine these issues in human
populations has more than doubled,
resulting in a larger database with which to
conduct a comprehensive assessment of the
potential effects which passive smoking
may have on the respiratory health of
adults as well as children.
Because only a very small number of
studies on the possible association between
exposure to secondhand smoke and heart
disease and other cancers existed in the
scientific literature at the time this
assessment was first undertaken, EPA has
not conducted an assessment of the possible
association of heart disease and passive
smoking. EPA is considering whether such
an assessment should be undertaken in the
future, but has no plans to do so at this
time.
Scientific Approach
EPA reached its conclusions concerning the
potential for ETS to act as a human
carcinogen based on an analysis of all of the
available data, including more than 30
epidemiologic (human) studies looking
specifically at passive smoking as well as
information on active or direct smoking. In
addition, EPA considered animal data,
biological measurements of human uptake
of tobacco smoke components and other
available data. The conclusions were based
on what is commonly known as the total
"weight-of-evidence" rather than on any
one study or type of study.
The finding that ETS should be classified as
a Group A carcinogen is based on the
conclusive evidence of the dose-related
lung carcinogenicity of mainstream smoke
in active smokers and the similarities of
mainstream and sidestream smoke given
off by the burning end of the cigarette. The
finding is bolstered by the statistically
significant exposure-related increase in lung
cancer in nonsmoking spouses of smokers
which is found in an analysis of more than
30 epidemiology studies that examined the
association between secondhand smoke and
lung cancer.
i
The weight-of-evidence analysis for the
noncancer respiratory effects in children is
based primarily on a review of more than
100 studies, including 50 recent
epidemiology studies of children whose
parents smoke.
Beyond the Risk Assessment
Although EPA does not have any
regulatory authority for controlling ETS, the
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Agency expects this report to be of value to
other health professionals and
policymakers in taking appropriate steps to
minimize peoples' exposure to tobacco
smoke in indoor environments.
In cooperation with other government
agencies, EPA will carry out an education
and outreach program over the next two
years to inform the public and policy
makers on what to do to reduce the health
risks of ETS as well as other indoor air
pollutants.
For Further Information
A limited number of copies of the complete
report can be obtained free of charge from:
Center for Environmental Research
Information (CERI)
U.S. EPA
26 W. Martin Luther King Drive
Cincinnati, OH 45268
Telephone: 513-569-7562
Fax: 513-569-7566
Ordering Number: EPA/600/6-90/006F
or
U.S. Environmental Protection Agency
Indoor Air Quality Information
Clearinghouse (IAQ INFO)
P.O. Box 37133
Washington D.C. 20013-7133
Telephone: 1-800-438-4318
Fax: 301-588-3408
A number of government agencies can
provide additional information addressing
the health risks of environmental tobacco
smoke. These include:
Office on Smoking and Health/Centers for
Disease Control
Center for Chronic Disease Prevention and
Health Promotion
Mail Stop K-50, 4770 Buford Highway
Atlanta, GA 30341
National Cancer Institute
Building 31, Room 10A24
Bethesda, MD 20892
1-800-4-CANCER
The National Heart, Lung, and Blood
Institute
Information Center
4733 Bethesda Avenue, Suite 530
Bethesda, MD 20814
National Institute for Occupational Safety
and Health
4676 Columbia Parkway
Cincinnati, Ohio 45226-1998
1-800-35-NIOSH
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