Although air quality PCD reports indicate that
Bangkok’s air pollution has improved somewhat in recent
years,19,20 the results of the present study imply that the level
remains unsatisfactory and show that further efforts are required
to reduce pollution and monitor adverse health effects.
The more hazardous portion of fine particles, namely,
PM2.5, has come into prominence only recently, and no Asian
country, including Thailand, has yet started routine monitoring
or set the standard for PM2.5. In this study, the EPA
provisional standard was used as the basis for our discussion,
namely, a PM2.5 24-hr average of 65 µg/m3 and PM2.5
annual average of 15 µg/m3
.
15 The number of sites and days
of measurement were limited. However, the level of PM2.5 at
the intersections of Bangkok in the H area was between 82
and 143 µg/m3
, far exceeding the U.S. standard, while the
TSP and PM10 levels were within the standard. Thus, despite
the latter findings, the control effort should be continued to
reduce health risks because PM2.5 was relatively high. This
suggests the necessity of air pollution control regardless of
the standard based on either PM2.5 or PM10.