Indoor Air Pollution - Air Pollution and Global Warming: History, Science, and Solutions - page 212

440,000 contracted it (People's Daily Online, 2005). In
the United States, black lung disease killed 75,000 coal
miners between 1968 and 2005 (National Institute for
Occupational Safety and Health, 2008). The death rate
averaged about 2,500 per year from 1968 to 1986, then
declined linearly to 650 per year in 2005. The decline
was due primarily to better ventilation and respiratory
protection for coal miners, as well as a decrease in the
number of miners. However, in 2005 and 2006, 9 per-
cent of miners with 25 years or more experience had
contracted the disease, an increase over the 4 percent
rate in the late 1990s. Measures to improve conditions
for coal miners in the United States started with the
Coal Mine Health and Safety Act of 1969 .Between
1969 and 2010, this act also resulted in payout of $45
billion to coal miners disabled due to black lung dis-
ease or their survivors through the Federal Black Lung
Benefits Program .Each year, more than 300,000 recip-
ients typically receive about $4,800 annually from the
program.

Figure 9.4. Three-dimensional rendered close-up of
dust mite. C

Sebastian Kaulitzki/Dreamstime.com.

mostly from outdoor trees, plants, grasses, and weeds.
Omnipresent indoor allergens are dust mite feces .Dust
mites (Figure 9.4) grow to adult size of about 250 to
350

mfrom an egg in about 25 days (D'Amado et
al., 1994). Their feces range in size from 10 to 40

9.1.11. Asbestos
Asbestos is a class of natural impure hydrated silicate
minerals that can be separated into flexible fibers (e.g.,
Figure 9.5). It is mined in open pits by blasting rock
until asbestos is exposed and removed by machines.
The raw asbestos mineral is waxy, greasy, and soft, but

m.
Agram of dust may contain up to 100,000 feces. The
allergen in dust mite feces is a protein in the intestinal
enzyme coating of the feces (Jones, 1999). Allergens in
airborne dust mite feces may exacerbate symptoms in
85 percent of asthmatics (Platts-Mills and Carter, 1997).
In cockroaches, the sources of allergens are body parts
and feces. Cat allergens are present in the saliva, dan-
der, and skin of the cat. Dog allergens are found in the
saliva and dander of the dog. Allergens from cats, dogs,
and cockroaches can trigger rapid asthmatic responses.

9.1.10. Coal Dust
Amajor worldwide health problem directly linked to
aerosol particles is coal workers' pneumoconiosis, the
medical name coined by British doctors studying the
disease in 1942. This disease was first referred to as
“miner's asthma” in 1822. The name was changed to
black lung disease in 1831 by medical workers who
examined the blackened lungs of deceased miners. Coal
workers develop black lung disease over many years of
exposure to coal dust .Thedustfirstbuilds up in air sacs
in the lungs then scars the sacs, making breathing dif-
ficult. Symptoms of the disease include chronic cough
and shortness of breath.
Black lung disease is the greatest occupational hazard
worldwide. Between the 1950s and 2005 in China alone,
140,000 miners died from the disease, and another

Figure 9.5. Unmilled rock sample of mineral asbestos.
C

Pancaketom/Dreamstime.com.