Civil Engineering Reference
In-Depth Information
2.4 Radon
Radon is covered in ''
Toxicity Issues: Radon
'
'. Hence, this section provides a brief
description of radon concerning IAQ, health effects and its main sources. Exposure
to common environmental radon levels causes no acute health effects (ATSDR
2013a
), but radon is nowadays classified as carcinogenic to humans by the IARC.
The main source of radon is the soil subjacent to the building, which may enter by
infiltration though openings, joints, and cracks (Mäkeläinen et al.
2001
). Water
supplies and granitic construction and decorative materials inside the building may
be considered minor sources of radon, so geological factors are decisive to indoor
radon concentrations (US EPA
2013d
). Radon is easily dispersed outdoors, but it
tends to accumulate indoors, especially in inadequately ventilated small spaces
(US EPA
2013c
). Hence, radon could be a problem of concern regarding energy
saving in the construction of new buildings and in the refurbishment of existing
ones (Pacheco-Torgal
2012
).
2.5 Particulate Matter
PM is a complex mixture of solid particles and liquid droplets, made of organic
and inorganic compounds. Indoor PM includes dust, smoke and biologic-related
particles or bioaerosols, such as pollen, dust mites, mould, bacteria and viruses
(Goyal and Khare
2010
). The size of the particles is directly linked with their
adverse health effects. Hence, PM is frequently classified as inhalable coarse
particles PM
10
(particles less than 10 lm in aerodynamic diameter), fine particles
PM
2.5
(particles less than 2.5 lm in aerodynamic diameter) and ultrafine particles
PM
0.1
(particles less than 0.1 lm in aerodynamic diameter). PM
10
and PM
2.5
are
used
for
compliance
monitoring,
while
PM
0.1
standardised
measurement
programmes have not yet been widely implemented (WHO
2005
).
When indoor sources are present, the concentration of PM indoors is frequently
higher than outdoors. Particularly, in developing countries indoor exposure to PM
from combustion of wood, charcoal and coal among others for heating and
cooking purposes exposes the population to high concentration of PM (Bruce et al.
2000
). Other indoor activities emitting PM and their particle size characterisation
are shown in Table
4
. Although indoor PM concentrations are mainly affected by
indoor activities, particles penetrating by infiltration and ventilation may be con-
sidered as an important contribution (Kopperud et al.
2004
).
PM
2.5
may be a better indicator of particle pollution than PM
10
, being a better
marker of both risk to human health and anthropogenic suspended PM (WHO
2005
). Figure
4
shows PM
2.5
concentrations inside buildings, homes and outdoors
from selected studies in the USA and Europe. In general, indoor concentrations are
higher than outdoors, except in the studies performed in Boston (Abt et al.
2000
)
and Oxford (Lai et al.
2004
), where indoor activities such as cooking, cleaning and
