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BEAM P
LUS FOR
N
EW
B
UILDINGS
I
NDOOR
E
NVIRONMENTAL
Q
UALITY
(I
EQ
)
V
ERSION
1.2
I
EQ
6 O
UTDOOR
S
OURCES OF
A
IR
P
OLLUTION
Copyright © 2012 BEAM Society Limited. All rights reserved.
Page 154
account is taken and that measurements will be taken under typical or
average climatic conditions.
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 outdoor sources. In the case of occupied/habitable rooms
in air-conditioned/naturally ventilated buildings the concern is indoor air
pollutant from outdoor sources whilst operating in the naturally ventilated
mode. Undertaking appropriate measurements in air-conditioned
buildings will demonstrate that the design and construction of the
building and services serve to reduce indoor air pollution from outdoor
sources.
CO is a toxic gas which interferes with the oxygen transport capacity of
the blood, and at levels to which people can be exposed in buildings,
leads to symptoms such as headaches, nausea, chest constriction, etc,
as well as affecting concentration. Exposure to oxides of nitrogen (NO
x
,
NO
2
) can result in irritations to the eyes and respiratory system. Sources
in occupied areas include infiltration from vehicle exhausts and enclosed
car parks, and incomplete combustion within premises. O
3
irritates the
eyes and respiratory system. Sources of ozone in occupied areas
include infiltration from outside occupied areas, and from equipment
which utilises ultra-violet light or causes ionisation of air.
Respirable Suspended Particles (PM
10
) are suspended airborne particles
with a nominal aerodynamic diameter of 10 µm or less. The health
impacts from inhalation of particles depend on size, shape and chemical
reactivity. Outdoor sources are numerous, but vehicular exhaust and
construction activity contribute significantly. Particulates from outside
sources are carried into air-conditioned buildings through outside air
intakes and through uncontrolled infiltration. Indoor sources include air
ducts, equipment and user activities. Levels of RSP may be used as an
indicator of the effectiveness of the air filtration system, sampling should
be carried out at one representative zone in each type of premises.
Survey data for Hong Kong buildings show that if design and
construction is adequate it should be possible to meet the Excellent
Class of the Guidance Note for CO, NO
2
, O
3
and RSP in new air-
conditioned buildings.