Abstract:
Environmental exposure to volatile organic compounds (VOCs) of Bangkok metropolitan residents was assigned to study in roadside and non-roadside areas of nine selected districts including Phakhanong, Yannawa, Chatuchak, Rajthavee, Bangkapi, Bangkok Noi, Bangkhae, Prawet and Khanna Yao. The sampling was performed during 20 to 27 July 2005. At each sampling site, three categories of samples were collected, outdoor, indoor and personal. VOCs samples were collected for 24 hours using passive gas tube. Each sample was taken to extracted with CS[subscript 2] and to qualitative and quantitative analysis by GC/Ms. Sixteen target VOCs could be found and six of those such as Benzene, Toluene, Ethylbenzene, m-Xylene, p-Xylene and o-Xylene were mainly observed in all study areas with the ranges of 18.9 76.1, 60.2 213.7, 2.6 15.9, 5.7 26.2, 4.1 21.5 and 3.7-18.9 us/m[superscript 3] respectively. For all samples categories, the results show that VOCs concentrations measured at roadside were relatively higher than those at non-roadside, except limonene which was found at non - roadside higher than at roadside. When compared outdoor VOCs concentration between of all study areas, high level of VOCs was found in Phakhanong (Sukumvit Rd.) and Chatuchak (Phaholyotin Rd.), while the concentration observed at Prawet (Srinakarin Rd.) and Bangkhae (Phetkasem Rd.) was low. However, indoor and personal VOCs concentration were not concoid with those presented at outdoor because difference of house characteristics and residents activity. Indoor/outdoor (I/O) ratios VOCs concentation of all residential in roadside and non-roadside areas were about 0.6 From analysis on correlation of average VOCs concentration of personal exposure to indoor and to outdoor, statistical significant coorelation of personal exposure to indoor was obtained. Predicted personal exposure level (Pi) using Time Weight Average equation showed relatively higher than those observe (Po) which was expressed as Po/Pi with the values of 0.5-0.8, except limonene.