Monitoring of on-road and roadside air quality in Bangkok Metropolitan Region for assessment of vehicle emission and associated health risk | |
| Author | Jira Kongpran |
| Call Number | AIT Thesis no.EV-11-05 |
| Subject(s) | Air quality--Thailand--Bangkok Health risk assessment--Thailand--Bangkok |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | Thailand is facing serious air pollution problem, especially in urban areas, mainly due to traffic emission. This study investigated levels of air pollutant at roadside and on-road vehicles in the relation to the traffic flow and the associated potential health effects. The average concentration for roadside PM2.5, benzene, toluene, ethylbenzene and xylene (BTEX), respectively were 25±6, 9.7±4.5, 30±13, 4.4±2.3 and 11±4.7 μg/m³ for the city center (Dindaeng Road) in wet season, 56±13, 6.9±2.9, 17±8.8, 2.3±1.2 and 5.9±3.1 μg/m³ for the city center in dry season, and 58±29, 5.3±3.1, 13.9±13.6, 2.3±1.7 and 3.7±2.7 μg/m³ for the suburban area (Phaholyothin Road) in dry season. Roadside PM2.5 concentrations in the city center during the dry season were higher than wet season but the BTEX levels did not show clear difference between the seasons. The levels of pollutants measured at Phaholyothin Road roadside in the suburban area were quite similar to those in the city center showing the dominance of traffic emission. The highest of roadside BTEX concentrations were found during 7-8 a.m. at both Dindaeng Road and Phaholyothin Road when the traffic volumes also peaked. On-road PM2.5 concentration in the city center during wet season measured inside the van (A/C off, open windows) was 55±44 μg/m³ which was lower than the concentration during dry season (141±48). On-road PM2.5 concentration in the city center were 69±44 and 101 μg/m³ for inside (A/C on, closed windows) and outside the pick-up (measured in the open back wagon), respectively, which higher than those measured in suburban area, 14±14 and 44±13 μg/m³ for inside and outside the pick-up, respectively. Inside the pick-up with window closed, the PM could enter through the A/C ventilation system only that filtered part of PM. This causes the concentration inside the pick-up was lower than outside. Thus, A/C should be switched on to reduce PM2.5 levels inside vehicles especially while traveling on polluted roads. The on-road average concentrations of benzene, toluene, ethylbenzene and xylene, respectively, in the city center route were 86±36, 245±107, 23±10 and 75±35 μg/m³ inside the pick-up, and 44±10, 109±37, 11±5.2,and 38±16 μg/m³ for outside the pick-up. Similar to the city center, on-road BTEX levels in the suburban route measured inside the pick-up were higher than the concentration outside the pick-up. BTEX, gas pollutants, cannot be absorbed by fabric filter of A/C system and they were accumulated inside the vehicle hence air cleaning devices are required to reduce the exposure. On-road monitoring for motorcycle driver show the highest levels of BTEX even though the measurements were in the suburban area which were 16±4, 39±12, 4.5±1.4, 14±6.2 μg/m³ for benzene, toluene, ethylbenzene and xylene, respectively. Inverse CALINE4 modeling produced the average fleet emission factor of benzene, toluene, ethylbenzene, m, p-xylene, o-xylene, NO₂ and SO₂ for the whole street fleet on Phaholyothin Road, free flow and open highway of 1.2±0.5, 3.4±1.5, 0.9±0.4, 1.3±0.7, 0.8±0.1, 23±12 and 29±12 mg/kg-vehicle, respectively. The PM2.5 and BTEX levels obtained in this study were used to assess the potential health risk. High levels of PM2.5 potentially pose the health risk, the Hazard Index (HI) values were found between 0.3-4.9, most of target groups were at risk (HI>1). For benzene, group-1 carcinogenic to human, the risk of the target group was between 2.1x10-9 to 1.9x10-7. This was at low risk level (risk below 0.01). For non-carcinogenic effect cause by BTEX, the HI values were found between 0.03-0.81. All target groups were not at risk due to BTEX exposure (HI<1). |
| Year | 2011 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Preeda Pakpian;Nguyen, Thi Kim Oanh; |
| Examination Committee(s) | Thammarat Koottatep; |
| Scholarship Donor(s) | Thailand (HM Queen); |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2011 |