Class Session XII>
I. Indoor Pollution
Indoor pollution refers to human
exposure to a wide variety of chemicals, substances, and gases which can be
harmful to human health. Indoor pollutants are not as easily dispersed or
diluted as outdoor pollutants are. As a result, concentrations can often be
many times higher than outdoors.
A wide range of chemicals,
substances, and gases are considered to be indoor pollutants. These include:
1. Radon - Radon is a naturally
occurring gas that emanates from uranium deposits in the earth and seeps upward
through soil. Radon gas gets "trapped" in buildings and the
concentration can increase over time. Radon gas has a long-term deleterious
effect on human lung function.
2. Tobacco Smoke - Cigarette,
cigar, and pipe smoke contains gases which affect lung function and can result
in long term impairment.
3. Biological Contaminants - Air
inside buildings often contain a wide range of biological microorganisms. These
microorganisms often do not affect human health. The concentrations of these
microorganisms can increase, however, or subtle changes can occur which render
these organisms harmful or toxic to humans. One of the best known cases is
"Legionnaires Disease" which first occurred at an American Legion
convention at the Bellevue Stratford Hotel in
4. Carbon Monoxide - Carbon
monoxide, or CO, often results whenever combustion occurs. Within buildings,
there are a number of combustion sources. These include boilers, hot water
heaters, furnaces, and wood stoves. Carbon monoxide reduces the ability of the
body's blood to absorb oxygen. It is also colorless and odorless making
detection difficult. Inhaling low levels of carbon monoxide can result in
fatigue and chest pain, particularly in individuals with chronic heart disease.
Increased exposure to CO can result in headaches, dizziness, sleepiness,
nausea, vomiting, and disorientation. At very high levels, inhalation of carbon
monoxide can cause loss of consciousness and death. Every year, several hundred
lives are lost in the
5. Household Products - A wide
range of household products such as cleaners, solvents, glues, paints and
polishes result in gases, odors, and fumes that can affect human health.
6. Formaldehyde - Building
products often contains glues and other substances that contain formaldehyde.
7. Pesticides - Fumigants, rodenticides, and other pesticides used within buildings
can contain chemicals that result in a wide range of human health effects.
8. Asbestos - Asbestos is a
building material that was widely used as a fire retardant. Asbestos contains
fiber which, when they become airborne, can result in cumulative lung damage.
9. Lead - Lead was widely used as
an additive for paint up through the 1970's. The danger with lead paint is when
it flakes or chips, or becomes volatile when removed by heat guns or chemical
strippers.
10. Nitrogen Dioxide - Nitrogen
dioxide or NOX, as it is more commonly known, results from the combustion of
natural gas, LP gas, kerosene, fuel oil, wood or coal. Combustion devices such
as furnaces, boilers, and hot water heaters must be properly vented to avoid
indoor build-up of NOX.
11. Particles - Almost all air
contains some particles, or particulates, as they are also known. Indoor
particulates can result from many sources including air conditioning systems,
heating and ventilation systems, and machinery.
Indoor pollution occurs in a wide
range of indoor environments including homes, schools, factories, office
buildings, and commercial workplaces. Excessive noise, dust, odors and fumes
can all serve to lower worker productivity and adversely affect human health.
The Occupational Safety and Health Administration, OSHA, regulates indoor
pollution within workplaces and the U.S.E.P.A. focuses on indoor air problems
within homes.
Indoor air pollution can affect
human health in many ways, ranging from headaches and breathing difficulties to
death. Some of these affects exhibit themselves immediately after exposure.
Others occur after long periods of exposure. Each person has a different level
of susceptibility to indoor air pollution. Some individuals are hardly bothered
while others have acute sensitivity to the smallest levels. Many variables, in
combination, determine likely health impacts from exposure. These include a
person's age, existing lung function, the concentration of pollutants, and the
duration of exposure.
Within residential buildings, a
variety of technologies are used to control indoor pollution. These include
measurement & monitoring devices such as carbon monoxide and radon
detectors, ventilation improvements, and home air cleaning equipment and
systems. Because there are many more indoor pollutants within workplaces,
particularly shops and factories, there are a large number of commercial scale
indoor air technologies. These include:
|
Air Handling Systems Filters, |
|
Mist Eliminators |
|
Air Humidifiers &
Dehumidifiers |
|
Monitoring Devices |
|
Clean Rooms |
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Respiratory Protection |
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Dust Suppression &
Collection |
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Sealing & Venting Systems |
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Filters, Reprocessed Indoor Air |
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Static Eliminators |
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Fume Extractors |
|
Ventilating & Air
Extraction Systems |
II. Local Air Toxics
There are numerous toxic trace
pollutants that are emitted from specific industries and thus present an air
quality problem in the vicinity of these industries. These pollutants include
heavy metals such as beryllium, cadmiun, and mercury,
organic compounds such as aldehydes and furans and
radioactive particles and gases. Occasionally, large-scale toxic emissions from
industrial facilities, such as the industrial accident in 1984 in
III. Technology and Air Toxics
A number of processes &
technologies are used to control local air pollutants and odors. Of particular
importance is detection equipment and systems as many of these compounds are
highly toxic to humans. Processes include distillation, extraction,
incineration, control, biofiltration, and removal.
Technologies include toxic gas analyzers, monitors and detectors, hoods,
exhaust systems, chemicals and scrubbers.