Determination of primary and secondary organic aerosols in the Bangkok Metropolitan Region with the focus on water soluble organic carbon | |
| Author | Dahal, Bidur |
| Call Number | AIT Thesis no.EV-08-3 |
| Subject(s) | Water-soluble organometallic compounds--Thailand--Bangkok Atmospheric aerosols--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 | Water soluble organic carbon (WSOC) constituent of atmospheric aerosols is of importance as it has the capacity to change the hygroscopic behavior of aerosol particles. This property of WSOC causes a range of effects like reducing visibility, climatic modulation, material and ecosystem damage, and adverse health effects. In this research the WSOC in 24-h PM₂.₅ at a suburban site (AIT, Pathumthani Province) of the Bangkok Metropolitan Region (BMR) in Thailand was determined. The measurement was conducted during both dry and wet season, from May 2007 to February 2008. The WSOC data was then used in combination with elemental carbon/organic carbon (EC/OC) data for the same samples to estimate the fraction of primary and secondary organic aerosols in ambient PM₂.₅. MiniVol air samplers were used to take around 180 PM₂.₅ samples for the analysis of mass and WSOC. Both Quartz and Teflon filters were used for the purpose. However, Teflon filters were found to be suitable for PM₂.₅ sample collection as it is least affected by artifacts while quartz filters were found good for WSOC analysis. Thus, reported here for mass is from Teflon and WSOC from Quartz. PM₂.₅ collected over Quartz filters was between 7- 123 ug/m³ with mean value 49±26 ug/m³ while for the Teflon filter, the data ranged from 3 - 93 ug/m³ with mean value of 24±19 ug/m³. The mass concentration of 24-h PM₂.₅ was higher in dry period than wet period and exceeded annual USEPA standards, WHO and Europe Air Quality guideline values. It was observed that the overall periods' average concentration of WSOC in PM₂.₅ was 9.1±5 ug/m³. This is approximately 20% of the total PM₂.₅ and 84% of total OC. OC concentration as calculated for this study period was also in the same range, i.e., 10.2±6 ug/m³. More intensive biomass open burning, stable atmosphere and higher photochemistry intensity may be the reason for higher WSOC and OC and higher PM₂.₅ mass during the dry season. A baseline OC/EC primary ratio of 1.27 was found. It was then applied in EC Tracer method to determine primary and secondary organic carbon. The concentration of the primary organic carbon (POC) ranged between 2.1 - 17.9 ug/m³ with an average of 7.4±4 ug/m³; while, the concentration for secondary organic carbon (SOC) was between 0 - 13.9 ug/m³ with an average of 3±4 ug/m³. The study found that the area contained higher POC than SOC. |
| 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 (EV) |
| Chairperson(s) | Nguyen, Thi Kim Oanh; |
| Examination Committee(s) | Thammarat Koottatep;Rupakheti, Maheswar; |
| Scholarship Donor(s) | ADB - Japan Scholarship Program (ADB-JSP); |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2008 |