Bus Commuters’ Exposure to Fine Particulate Matter and Ozone in Bangkok

Abstract:

Personal air pollution exposures were conducted along traffic routes in Bangkok in comparison to the ambient monitoring data. This study aimed to get a better understanding of the health risks posed by fine particulate matter, PM2.5, PM10 and ozone in the urban transport micro-environment. The exposure pollutants were measured on the non-air condition buses during evening rush hours from 4.00pm to 8.00pm in November 2007 – January 2008. The studied bus routes were selected from traffic volume, 25,000-60,000 car/day urban streets with averaged vehicle speed 14 km/hour. Air pollution exposures were varied among traffic conditions. PM2.5 and PM10 were collected using personal air sampler attached size-selected cascade impactor. Ozone was absorbed through the passive gas sampler followed by the ion chromatography analysis. Hourly PM2.5 and PM10 commuters’ exposures were found 43.0 ± 7.4 and 58.2 ± 8.4 µg/m3, (n = 18) respectively. Ozone exposures were found relatively within the National Ambient Air Quality Standard (100 ppb). Hourly O3 individual exposures in traffic routes averaged were 44.2 ± 18.9 ppb, (n = 16). Fixed monitoring stations were found to be relatively low predictors of PM2.5, PM10 and O3 exposure concentration levels experienced by individuals.

Keywords: fine particulate matter, PM2.5, PM10 , ozone, Bangkok