Roadside air quality in Ho Chi Minh City and vehicle emission estimation by back calculation | |
| Author | Nguyen Tran Huong Giang |
| Call Number | AIT Thesis no.EV-08-25 |
| Subject(s) | Roadside ecology--Vietnam--Ho Chi Minh Air quality--Vietnam--Ho Chi Minh |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Environmental Technology and Management |
| Publisher | Asian Institute of Technology |
| Abstract | Ho Chi Minh City (HCMC), the largest city in Vietnam, in recent years faces with alarming air pollution problems caused by the vehicular exhaust emissions. The roadside air pollution characterization and vehicle emission estimation become prerequisites since they provide the information for establishing the emission inventory, setting up the priority sources for abatement and designing effective control strategies. This study aims, therefore, to characterize the roadside air quality in relation to traffic volume, and to determine vehicle emission factors with the focus on toxic air pollutants including PM2.5 and BTEX (benzene, toluene, ethylbenzene. and xylenes). The roadside PM2.5 and BTEX pollutions were monitored in relation to traffic volume at a typical urban street in Ho Chi Minh City (HCMC), Vietnam. The 24-h PM2.5 concentration was 53 - 129 while 8-h PM2.5 concentration was 50 - 170 ug/m³. The hourly levels of benzene, toluene, ethylbenzene, m,p-xylenes and o-xylene varies between 6 - 53, 14 - 170, 3 - 24, 5 - 59, and 2 - 21 ug/m³, respectively within a day. During daytime higher concentrations were observed on weekdays than weekend but the opposite was observed at nighttime and early in the morning when weekend had higher concentrations. This corresponds to the variations in traffic volume between weekday and weekend. Pollution levels measured within 30 m from the traffic lane were found to reduce with increasing downwind distance. Principal component analysis (PCA) was applied to the set of air pollution and traffic volume data which revealed that PM2.5 is associated with the diesel fueled vehicles (truck and bus) while BTEX were linked to gasoline fueled vehicles (motorcycle. car. and delivery tricycle). Van had good correlation to both PM2.5 and BTEX level as it uses both diesel and gasoline fuel. Inverse CALINE4 modeling produced the average emission factors of PM2.5, benzene, toluene, ethylbenzene, m.p-Xylene, and o-Xylene for the whole street fleet of 38 ± 3.9; 23 ± 4.3; 74 ± 14.8; 8 ± 1.3; 28 ± 9.5, and 9 ± 2.5 mg/vehicle.km which correspond to hourly fleet emission ranges during a day of 141 - 388: 18 - 435; 52 - 1493; 6 - 131; 18 - 655; and 6 - 194 g/km.hour, respectively. Solving multilinear equations system constructed based on the hourly fleet emission and fleet composition, emission factors for gasoline and diesel vehicle categories were obtained. The gasoline fueled vehicles had lower PM2.5 but higher benzene, toluene, ethylbenzene, m,p-Xylene, and o-Xylene, namely, 25 ± 2.4; 22 ± 0.1; 68 ± 0.3; 8 ± 0.1; 22 ± 0.1, and 8 ± 0.1 mg/km, respectively. While for diesel fueled vehicle the corresponding emission factors were 388 ± 164.0; 17 + 5.3; 61 ± 22.2; 4 ± 3.3; 20 ± 5.5 and 5 ± 2.9 mg/km, respectively. |
| Year | 2008 |
| 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) | Nguyen, Thi Kim Oanh; |
| Examination Committee(s) | Visvanathan, C.;Preeda Pakpian; |
| Scholarship Donor(s) | Ministry of Education and Training (MOET), Vietnam;Asian Institute of Technology Fellowship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2008 |