Indoor
Human Health Risks:
The EPA's Vision for the 21st Century
REUTERS - The Environmental
Protection Agency 's Draft Final Report," Healthy Buildings, Healthy
People: A Vision for the 21st Century " is a call to action for
us all to work together to improve the indoor environment. The risks
associated with poor indoor air qualityasthma, cancer, reproductive
and development problems, and other health effectsare explained
in the following Chapter 1 of the Report.
Asthma
An estimated 27 million
Americans suffer from asthma (U.S. EPA 1999). In addition, about 5,000
deaths occur yearly from asthmaan increase of 33 percent in the
last decade (Mannino et al. 1998). Consequently, the social and economic
costs are large. Among chronic diseases, asthma is the number one cause
of absenteeism from school (Pope et al. 1993). Asthma cost an estimated
$6.2 billion in the United States in 1990, including direct medical and
indirect non-medical costs combined. An update of this figure would fall
in the range of $7 to $9 billion in 1998 dollars (Weiss et al. 1992).
Some groups in this
country (e.g., children, certain minorities, seniors, and low-income,
urban populations) are disproportionately affected by asthma. An estimated
1.8 million people required emergency room services for asthma in 1995.
Mortality rates associated with asthma among African-Americans, as a
whole, are two- to three-fold higher than those among whites. Mortality
rates for African-American children are fivefold higher than those for
their white peers (Mannino et al. 1998). While research has not yet explained
the rise in the incidence of asthma, nor all the reasons why individuals
first contract it, there is general agreement that controlling indoor
exposures is an important protective measure (NAS 2000).
Recently the National
Academy of Sciences/Institute of Medicine issued a report on asthma and
indoor air quality, confirming that dust mites and other allergens, microorganisms,
and some chemicals found indoors are triggers for asthma. In addition,
the report stated there was sufficient evidence regarding associations
between ETS, in preschool-aged children, and house dust mites and the
development of asthma (NAS 2000). ETS may significantly aggravate symptoms
of asthma for 200,000 children and may affect as many as 1,000,000 children
to some extent (U.S. EPA 1992).
Cancer
A number of indoor contaminants,
such as asbestos, radon, tobacco smoke, and benzene, are known human
carcinogens. Other indoor contaminants, such as certain chlorinated solvents,
polycyclic aromatic hydrocarbons, aldehydes, and pesticides, are considered
likely to cause cancer in humans.
The National Academy
of Sciences, in its latest report on radon health science (NAS 1998),
concluded that radon is the second leading cause of lung cancer in the
country. NAS has estimated that about 12 percent of the lung cancer deaths
in the United States are linked to radon. They calculate the number of
lung cancer cases attributable to radon exposure to range from 15,000
to 22,000 annually.
Environmental tobacco
smoke is estimated to cause an additional 3,000 lung cancer deaths in
nonsmokers each year (U.S. EPA 1992). Other forms of cancer have also
been found to be associated with indoor pollutants (e.g., leukemia with
benzene; bladder cancer with ETS).
Reproductive and Developmental Effects
During the period 1991
to 1994, almost 900,000 children had elevated blood levels, which can
cause a variety of developmental delays, including effects on intelligence
quotient (IQ); vision, hearing and stature deficits; and learning disabilities
(U.S. DHHS 1997a). Several studies indicate that common indoor pollutants
such as lead and ETS can also impair fetal development. A California
report estimates that 9,700 to 18,600 cases of low birth weight in infants
are caused each year by ETS (NCI 1999).
Many other environmental
agents, including a number of chemicals commonly found indoors (e.g.,
tobacco smoke, some pesticides, lead and other heavy metals, alcohols,
and plastic additives), are suspected of causing developmental toxicity
in humans (U.S. EPA 1991a, NCI 1999). Endocrine disruptors (e.g., certain
pesticides and plasticizers), which affect the normal function of sex
and thyroid hormones, present a new area of concern for reproductive
toxicity. Adverse effects on a developing child may result from exposure
prior to conception in either parent, exposure during pregnancy, or post-natal
exposure. These effects range from low birth weight to genetic diseases
to lower IQs and infertility.
While the proportion
of reproductive and developmental effects due to indoor environmental
factors is currently unknown, the impact could be serious. Approximately
3 percent of newborn children have one or more significant malformations
at birth. By age one, about 3 percent more are recognized to have serious
developmental defects. Lifetime health-care costs for children born each
year with birth defects are estimated to be more than $8 billion.
Other Health Effects
Indoor environments
can cause or amplify many other health effects as well. The American
Heart Association estimates that 35,000 to 40,000 cardiovascular deaths
per year among nonsmokers can be attributed to ETS exposure (Taylor et
al. 1991). Recent studies have shown that, compared to those who had
not been exposed, ETS was associated with a 20 percent increase in the
progression of atherosclerosis (hardening of the arteries) (Howard et
al. 1998). Carbon monoxide (CO) poising associated with the improper
use and maintenance of fuel-burning appliances kills more than 200 people
per year in this country and results in about 10,000 admissions to hospital
emergency rooms for treatment (U.S. CPSC 1997). An additional 600 to
700 accidental deaths from CO poisoning occur indoors from other sources,
including automobiles (Cobb and Etzel 1991). The agent for Legionnaires'
disease, a potentially deadly pneumonia which affects 10,000 to15, 000
people each year, is associated with cooling systems, whirlpool baths,
humidifiers, food market vegetable misters, and other indoor sources,
including residential tap water (EPA et al. 1994; U.S. DHHS 1997b). Effects
associated with toxins from indoor fungi and bacteria range from short-term
irritation to immunosuppression and cancer (EPA et al. 1994).
Studies show that symptoms
of sick building syndrome (SBS) may be caused
or intensified by indoor environmental problems (U.S. EPA 1991b, U.S.
EPA et al. 1994). The term "sick building syndrome," first
employed in the 1970s, described a spectrum of specific and nonspecific
complaints reported by a population of building occupants. These symptoms
can be associated with their presence in the building. These complaints
may also result from causes other than SBS, including illness contracted
outside the building, acute sensitivity (e.g., allergies), job-related
stress or dissatisfaction, and other factors. Data are insufficient to
thoroughly evaluate many SBS problems.
References
United States Environmental
Protection Agency, Office of Air and Radiation, EPA Report 402-K-00-002,
March 2000
Source: Aerias:
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