Environmental Engineering Reference
In-Depth Information
people in developed countries typically spend 70-98%
of their time indoors or inside vehicles.
As a result of these studies, in 1990 the EPA placed
indoor air pollution at the top of the list of 18 sources
of cancer risk—causing as many as 6,000 premature
cancer deaths per year in the United States. At greatest
risk are smokers, infants and children younger than
age 5, the old, the sick, pregnant women, people with
respiratory or heart problems, and factory workers.
Danish and U.S. EPA studies have linked air pol-
lutants found in buildings to dizziness, headaches,
coughing, sneezing, shortness of breath, nausea, burn-
ing eyes, chronic fatigue, irritability, skin dryness and
irritation, and flu-like symptoms, known as the
sick-
building syndrome.
New buildings are more commonly
“sick” than old ones because of reduced air exchange
(to save energy) and chemicals released from new car-
peting and furniture. EPA studies indicate that almost
one in five of the 4 million commercial buildings in the
United States is considered “sick.” Mold spores that
grow in damp places are probably the greatest cause of
allergic reactions to indoor air pollution. Such molds
can flourish in air ducts and when moisture becomes
trapped in the walls of airtight houses.
The solution is not to give up on improving en-
ergy efficiency in buildings. Instead, air heat exchang-
ers should be used to provide a healthy flow of air
inside homes and other buildings without affecting
overall heat gains and losses in such structures. Hav-
ing outdoor vents in kitchens and bathrooms also
helps reduce the indoor buildup of moisture and air
pollutants from cooking. Gas and oil furnaces should
be checked for carbon monoxide production, and
homeowners should install carbon monoxide detec-
tors and warning devices near bedrooms. Homeown-
ers can also put a plastic cover over dirt in crawlspaces
to reduce inputs of moisture from the ground and use
vents to ensure that crawlspaces are well ventilated.
According to the EPA and public health officials,
the four most dangerous indoor air pollutants in de-
veloped countries are
cigarette smoke
(Case Study,
p. 327),
formaldehyde, radon-222 gas
(Case Study, p. 358
),
and
very small fine and ultrafine particles.
The chemical that causes most people in devel-
oped countries difficulty is
formaldehyde,
a colorless,
extremely irritating gas widely used to manufacture
common household materials. According to the EPA
and the American Lung Association, 20-40 million
Americans suffer from chronic breathing problems,
dizziness, rash, headaches, sore throat, sinus and eye
irritation, wheezing, and nausea caused by daily expo-
sure to low levels of formaldehyde emitted from com-
mon household materials.
The many sources of
formaldehyde
include build-
ing materials (such as plywood, particleboard, panel-
ing, and high-gloss wood used in floors and cabinets),
furniture, drapes, upholstery, adhesives in carpeting
Solutions
Acid Deposition
Prevention
Cleanup
Reduce air
pollution
by improving
energy
efficiency
Add lime to
neutralize
acidified lakes
Reduce coal use
Add phosphate
fertilizer to
neutralize
acidified lakes
Increase natural
gas use
Increase use of
renewable energy
resources
Burn low-sulfur
coal
Remove SO
2
particulates
and NO
x
from
smokestack gases
Remove NO
x
from
motor vehicular
exhaust
Tax emissions
of SO
2
Figure 15-11
Solutions:
methods for reducing acid depo-
sition and its damage.
Critical thinking: which two of these
solutions do you believe are the most important?
15-5
INDOOR AIR POLLUTION
Science: Indoor Air Pollution
Indoor air pollution usually poses a much greater
threat to human health than outdoor air pollution.
If you are reading this topic indoors, you may be inhal-
ing more air pollutants with each breath than if you
were outside. Figure 15-12 (p. 358) shows some typical
sources of indoor air pollution in a modern home.
EPA studies have revealed some alarming facts
about indoor air pollution in the United States.
First,
levels of 11 common pollutants generally are two to
five times higher inside homes and commercial build-
ings than outdoors and as much as 100 times higher
in some cases.
Second,
pollution levels inside cars in
traffic-clogged urban areas can be as much as 18 times
higher than outside.
Third,
the health risks from expo-
sure to such chemicals are magnified because most
