is 120 µg/m3, and the annual average (arithmetic mean)
is 50 µg/m3.
21 Analysis of the data between 1997 and 1999
indicates the average 24-hr PM10 level in Bangkok monitored
at the roadside stations exceeded the Thai standard
on more than 10% of days, and in most of the stations,
the annual level of PM10 exceeded the NAAQS. Although
there are high-volume air samplers (the method required
by the NAAQS) at some PCD stations, because of the lower
value obtained from the b-ray attenuation data compared
with our active pump sampling measurement, the PM
exposure of traffic police assessed by PCD data may be an
underestimate for personal exposure concentrations.
Therefore, this is the first report to show the actual fine
particulate exposure in the high-risk group
is 120 µg/m3, and the annual average (arithmetic mean)
is 50 µg/m3.
21 Analysis of the data between 1997 and 1999
indicates the average 24-hr PM10 level in Bangkok monitored
at the roadside stations exceeded the Thai standard
on more than 10% of days, and in most of the stations,
the annual level of PM10 exceeded the NAAQS. Although
there are high-volume air samplers (the method required
by the NAAQS) at some PCD stations, because of the lower
value obtained from the b-ray attenuation data compared
with our active pump sampling measurement, the PM
exposure of traffic police assessed by PCD data may be an
underestimate for personal exposure concentrations.
Therefore, this is the first report to show the actual fine
particulate exposure in the high-risk group
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