Transcript EHS500.IndAirPoll.m3

Health Effects of ETS
 Nonsmokers are exposed to ETS, the mixture of smoke from the
smoldering cigarette and exhaled smoke.
 This complex mixture contains many of the injurious agents
inhaled by active smokers, although the concentrations are
diluted.
 Nonsmokers exposed involuntarily to ETS often have
detectable levels of nicotine and of cotinine, a metabolite of
nicotine, in body fluids (blood and urine)
 Studies of smoking parents and their children provided the
first evidence that passive smoking has adverse health
effects.
 Maternal smoking was found to place infants at increased
risk for lower respiratory tract infections
 smoking by household members, particularly the mother,
was shown to increase the incidence of chronic
respiratory symptoms and reduce the level of lung
function in children.
 Other studies showed that ETS irritates the upper
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respiratory tract and eyes
Health Effects of ETS
 Increased risk of lung cancer for exposed nonsmokers
("passive" smokers) was first reported in 1981. Since then,
many studies have addressed this association; pooling of
the data indicates that nonsmokers married to smokers
have about a 25% greater risk of lung cancer than those
married to "never smokers".
 Several studies have suggested that ETS exposure reduces
lung function in nonsmokers and increases the risk for
ischemic heart disease.
 Other proposed associations of involuntary smoking with
disease include increased risk for cancers at sites other than
the lung, younger age at menopause, increased risk for
sudden infant death syndrome, and reduced birth weight.
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Health Effects of Nitrogen Dioxide
 Nitrogen dioxide is an oxidant gas that at high
concentrations causes lung injury.
 Toxicologic studies have shown that it reduces the
efficacy of lung defense mechanisms against infection.
Some studies suggest that short-term exposure may
exacerbate asthma.
 Thus, the potential health effects of exposure to
nitrogen dioxide indoors include:
 increased respiratory tract infection from effects of
defense mechanisms
 increased respiratory tract symptoms, and reduced lung
function from direct inflammation
 deterioration of the health status of persons with chronic
respiratory diseases, particularly asthma
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Health Effects of Microbiologic Agents
 Biologic agents represent an extremely diverse
group that cause disease primarily through
infection and immune mechanisms.
 The potential for transmission of many infectious
diseases through inhalation of indoor air has been
recognized for many years (‘common cold’, TB, etc.).
 Hypersensitivity pneumonitis and humidifier fever have
been linked to central and room humidifiers,
contaminated heating and cooling systems, moisturedamaged building materials, cool mist vaporizers, and
automobile air conditioning systems.
 Legionnaires' disease, an acute bacterial infection
caused by Legionella pneumophila, was first described
following an 1976 epidemic in Philadelphia. Airborne
transmission of this organism from contaminated water
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in cooling towers is well documented.
Health Effects of Microbiologic Agents
 Biologic aerosols in buildings may give rise to a
variety of syndromes ranging from malaise to
infective pneumonias.
 Example: in a survey of 12 town halls in Denmark,
general dizziness and concentration problems, as well
as mucous membrane irritation of the upper respiratory
tract were associated with the concentration of Gramnegative bacteria (endotoxin) in surface dust samples
 Asthma may be exacerbated by allergens in outdoor
and indoor air
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The major allergen house dust mite has been linked to
exacerbation of asthma in a large number of studies, and
asthma causation has been suggested by a few studies.
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Insects such as cockroaches are now
recognized as an important source of
allergens, primarily in urban housing
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Cat dander causes symptoms in many asthmatics. It is a
sticky allergen which can be detected in homes cat-free for
many months, as well as in schools.
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Health Effects of Formaldehyde and Other
VOCs
 Controversy remains concerning the health effects of these
indoor pollutants
 Formaldehyde is known to be toxic at high concentrations
and to be irritating to the respiratory tract
 Associations with respiratory morbidity and neurobehavioral
impairment, demonstrated in some studies, have not yet been
conclusively established.
 Formaldehyde causes nasal cancer in rats exposed to high
concentrations and is a suspected occupational carcinogen
 Airborne formaldehyde acts as an irritant to the conjunctiva
and upper and lower respiratory tract.
 Symptoms are reversible and, depending on the level and
length of exposure, may range from burning or tingling
sensations in the eyes, nose, and throat to chest tightness
and wheezing.
 The other VOCs may also have short- and long-term health
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effects, but human data are largely lacking.
Health Effects of Pesticides
 Pesticides sold for household use, notably impregnated
strips, and foggers, or insecticide "bombs" (technically
classified as semi-VOCs), include a variety of chemicals in
various forms.
 Exposure to pesticides are most likely to cause harm if they
are used improperly
 However, exposure via inhalation of spray mists may also
occur during normal use.
 Children in close contact with contaminated surfaces are at
risk of exposure via inhalation of vapors and contaminated
dusts, as well as through skin absorption.
 Symptoms may include headache, dizziness, muscular
weakness, and nausea
 Some pesticides have active ingredients and inert components
which are considered possible human carcinogens.
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Health Effects of Radon
 The effect of concern is lung cancer
 Inhalation of radon and its daughters results in localized
exposure of respiratory tract epithelial tissue to ionizing
radiation (alpha particles)
 Radon is estimated to cause about 14,000 deaths per
year in the U.S. (range of estimates from 7,000 to
30,000)
 This makes radon second only to tobacco smoking as
an environmental risk factor for lung cancer
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Ambient Versus Indoor Air Pollution:
Magnitudes of Health Effects
 Numerous studies have repeatedly found statistically
significant relationships between fluctuations in ambient
air pollution measures, most often particulate and ozone,
with acute increases in cardiorespiratory morbidity and
mortality.
 However, the magnitude of the found effects have
generally been modest, in the order of five to, at most,
40 percent increases.
 Much stronger associations have been demonstrated for
certain indoor air pollutants.
 These associations have been particularly strong for the
relationship of allergen content in house dust and
morbidity rates among children with asthma who have
demonstrated sensitization to the allergens present in
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the dust.
The Role Of Cockroach Allergy and Exposure To Cockroach Allergen In
Causing Morbidity Among Inner-city Children With Asthma
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Interactions between Ambient and Indoor
Air Pollution
 There is intriguing evidence that fluctuations in ambient
pollution levels may potentiate the ability of allergens
present in household dust to precipitate inflammatory
responses and asthma attacks in sensitized children. For
example:
 Pre-exposure to ozone has been shown to increase
bronchial responsiveness to allergens in two human
experimental studies.
 Diesel exhaust particulate has been shown to enhance
antigen-induced airway inflammation in mice
immunized with mite allergen, and to increase markers
of inflammation upon ragweed antigen challenge in
allergic human subjects.
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Control of Indoor Air Pollutants
 Control strategies are often complex, highly
variable, and specific dependent on the pollutants
of concern and their sources
 While, in general, control strategies are beyond
the scope of this presentation, the following chart
will give a flavor for the various approaches
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Pollutant Control Measures
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