Distribution of Fine Particulate Matter, PM2.5 and PM10 at Bangkok Mass Transit System Stations
Fine Particulate Matter, PM2.5 and PM10 were measured at three Bangkok Mass Transit System (BTS) stations, namely, Phayathai, Phrakanong and Chongnonthee. Those selected sampling sites had difference ambient particulate matter levels. The air samples were collected by low flow personal air samplers attached size selected cascades. The co-measurements of low flow air samplers were conducted parallel with beta- attenuation for PM10 and TEOM (R&P single channel sampler) for PM2.5 at some selected PCD monitoring stations. The ratio of our air samplers to PCD data PM10 and PM2.5 were 1.26 (SD=0.07) and 1.28 (SD=0.09), respectively. The 24 hour average fine particulate matters on weekday were found higher than those on weekend. The concentrations were associated with the traffic volume under the BTS stations. The PM vertical concentration was decreased with the increasing height. For example, at Phrakanong station, a highly polluted and congested site, 27 weekdays PM10 1st, 2nd and 3rd floor concentrations were 102.4 (SD=13.4), 61.9 (SD=4.0) and 45.1 (SD=5.4) microgram/m3, respectively. In addition to the height, the distribution of particulate matter concentrations were also related to traffic volume and the construction environment of each BTS stations.