Four street sampling stations in the Bangkok Metropolitan
Region (BMR) were chosen based on traffic density, flow
conditions and wind speed. Individual locations of sampling
stations are described in Figure 1. At all of these sites, the
measured air pollutants were particulate matter (PM10), carbon
monoxide (CO), nitrogen dioxide (NO2), sulphur dioxide (SO2),
ozone (O3) and benzene. Field measurements of air pollutant
levels in Bangkok streets were spread over the period from
January to December, 2001. In each monitoring station, on-line
analyzers were used to monitor continuously various air
pollutants and the data recordedfor sessions of hourly, daily
(weekday), weekend and monthly. The system provides four