Determination of ambient air concentrations and personal exposure risk levels of outdoor workers to carbonyl compounds and BTEX in the inner city of Bangkok, Thailand

Özet

The ambient and personal air concentrations of benzene, toluene, ethylbenzene and xylenes (BTEX) andcarbonyl compounds (CCs) were investigated in Pathumwan district, Bangkok (Thailand), a congestedarea with a high level of traffic-related air pollution. The potential health risk of three representativegroups of street workers (street vendors, motorcycle taxi driver and security guards) exposed to thesesubstances was estimated. The personal air exposure and ambient air samples were collected in the rainy(September 2012) and summer (March 2013) seasons. The 8-h average formaldehyde and acetaldehydeexposure levels for both personal and ambient air concentrations were found to be the major CCs. Thehighest mean ambient air level of formaldehyde (20.1 mg/m3) was found at the roadside at a busyintersection next to department stores. The highest level of acetaldehyde (9.17 mg/m3) was found in alocation with a high traffic load close to the hospital and university. For BTEX, the greatest averageconcentration was observed around the site located near a bus stop (45.5 mg/m3). In terms of the personalexposure concentrations of CCs and BTEX, no statistically significant differences were found among allsampled locations for street vendors and motorcycle taxi drivers. With respect to the health riskassessment, at a 95% confidence interval (CI) of cancer risk, benzene posed the highest risk followed byformaldehyde and then acetaldehyde (5.36E-06e1.48E-05, 5.58E-06e1.91E-05 and 1.03E-05e5.93E-05for street vendors, motorcycle taxi driver and security guards) while the 95% CI non-cancer risk valueswere at an acceptable level. Nevertheless, there were no significant differences in the total cancer riskamong the different groups of workers. From the health risk assessment, benzene and formaldehydewere the major traffic related air pollutants that likely affected the human health in this area.