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BEAM P
LUS FOR
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UILDINGS
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NDOOR
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NVIRONMENTAL
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UALITY
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V
ERSION
1.2
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EQ
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I
NDOOR
S
OURCES OF
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IR
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OLLUTION
Copyright © 2012 BEAM Society Limited. All rights reserved.
Page 156
place whilst operating in the background ventilation mode, or where
there is no specific provision for background ventilation, with all windows
and doors closed.
Where it can be demonstrated that the identified pollutants are unlikely to
exceed the limits prescribed, and as determined from an appropriate
sample of measurements, relevant credit(s) shall be awarded.
B
ACKGROUND
This section deals with pollutants found in indoor air, which are mainly
attributable to indoor sources. In the case of occupied/habitable rooms in
air-conditioned/naturally ventilated buildings the concern is indoor air
pollutant from indoor sources whilst operating in the background
ventilation mode, i.e. all openings other than those provided for
background ventilation are ‘closed’.
VOCs includes hundreds of chemical compounds found in indoor
environments from trace levels to levels that can cause various
symptoms such as eye and throat irritations, respiratory problems,
headaches, etc. Reactions can occur as a result of exposure to a single
sensitizing dose or sequence of doses, even at low levels. VOCs may
enter from outdoors, but are more likely to be emitted from building
materials, finishes and furnishings, pesticides and cleaning products.
HCHO is a type of volatile organic compound which is separately
identified due to its abundance in many building materials, adhesives,
fabrics and carpets, etc. HCHO is a suspected human carcinogen, and in
sufficiently high concentrations is known to cause eye, nose and
respiratory irritation and sensitisations. Since formaldehyde is most likely
to come from indoor sources, sampling should be carried out in at least
one representative zone of each type of occupied area.
Rn is a colourless radioactive gas that exhibits no taste or smell. There is
concern that exposure to elevated levels of Rn indoors increases the risk
of lung cancer. Rn is mainly emitted from granite and marble which are
major building materials in Hong Kong. The concentration of Rn may
accumulate to an unaccepted level in an enclosed space without
adequate ventilation. Choice of building materials and surface coverings
can have significant impact on emission rates. Since outdoor Rn
infiltration is minimal. Rn and its progenies are mainly generated indoors.