Civil Engineering Reference
In-Depth Information
these special characteristics, it has been widely used in a variety of manufactured
goods, such as building materials (roofing shingles, ceiling and floor tiles, water
supply lines), automobile clutches and brakes, and electrical and thermal insulating
materials among others (Virta
2006
).
Asbestos can be emitted by both natural sources, by erosion of asbestos or
asbestiform rocks, and anthropogenic sources, such as unsealed hazardous waste
landfills, and deterioration of building materials or car clutches and brakes
(Bourdès et al.
2000
). Asbestos fibres are neither volatile nor soluble, but they can
occur in suspension both in air and in water and, being very stable, they may
remain suspended for long periods and, hence, small quantities of asbestos are
ubiquitous in the air (ATSDR
2013b
).
Concentrations of asbestos fibres outdoors are variable (see Fig.
1
), as well as
indoors, depending on the presence of asbestos-containing building materials and
their condition. Indoor concentrations of (WHO
2010
) asbestos are generally
greater than outdoors. High concentrations of asbestos can be found when released
from building materials. Over time asbestos-containing materials may lose their
adhesion and may be damaged, increasing the probability of releasing asbestos
fibres to the environment, especially when during renovation and even after
renovation (Hoppe et al.
2012
).
Although asbestos was not included in the last WHO guideline for IAQ (2010),
because there was no sufficient evidence for IAQ guidelines, it was included in the
Air Quality guidelines for Europe (WHO
2000
) developed to assess risk of air
pollution in Europe. There is no evidence of acute effects of exposure to asbestos,
but it has been reported that long-term exposure to asbestos can cause respiratory
diseases, such as lung cancer, mesothelioma - a rare form of cancer that involves
the proliferation of mesothelial cells - and asbestosis - progressive and long-term
INDOORS
OUTDOORS
0.1
0.01
0.001
0.0001
0.00001
0.000001
Fig. 1 Asbestos average concentrations in different outdoor and indoor environments. Boxes
represent the range of average concentrations: (1) ATSDR (
2013b
), (2) Hoppe et al.
2012
