| Author | Narachan Pimsuca |
| Call Number | AIT Thesis no.EV-13-15 |
| Subject(s) | Acid deposition--Thailand
|
| 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 |
| Series Statement | Thesis ; no. EV-13-15 |
| Abstract | Acid deposition is the primary result of precursor air pollutants such as sulfur dioxide and nitrogen oxides which are mainly emitted from anthropogenic activities. Songkhla Lake is the largest lagoon in Thailand with large natural resources and rich in biodiversity. Urbanization and industrialization in Songkhla Lake Basin (SLB), recently, have lead to the increase of energy consumptions and the resulting higher air pollution emissions. This may lead to acid deposition which affects the ecosystem in the lake. This study applied an integrated approach to assess the acid deposition over the lake. The main tasks included conducting emission inventory of the Southern Thailand and application of 3D photochemical dispersion model (MM5-CAMx). The emission inventory, using semi-bottom-up approach, showed that the total SO₂ emission is 2,672 tons/year, and total NOx emission is 16,038 tons/year. The fine domain covered 33,088 km² (188 x 176 km) and 47 x 44 grid points with a resolution of 4 x 4 km. This domain covered the SLB area in the whole of Phattalung and Songkhla province and some area of Nakhon Si Thammarat and its surrounding provinces in the Southern region of Thailand. The modeling system was applied to simulate acid deposition over SLB for 2 months, February 2010 to represent the dry season and September 2010 for wet season. The MM5 model output was compared to the PCD air quality station (Hat Yai municipal) and TMD station (Hat Yai station). The modeled temperature as compared to the observation showed that the model results in February met the statistical criteria while the September results did not meet the criteria. The correlation in February or dry month of both stations is quite significant with high R2 values (0.79 and 0.80 respectively) while the lower R2 value was observed in both stations for September or wet month (0.49 and 0.51 respectively). For solar radiation, the model in the PCD station (no data in the TMD station) was able to reproduce observations with a slight tendency of overestimation for some days in both months. The R2 values for both months were 0.76 and 0.63 respectively. For wind speed, the model in the TMD station tended to overestimate for both months that has not met the criteria. The R2 between simulated wind speed and the observation were as low as 0.2 for February and lower (0.18) for September. However, overall model predicted higher wind speed as compared to the observed data which was common for a mesoscale meteorological model like MM5. The MM5-CAMx model output included ambient air concentration levels of SOx and NOx, and acid deposition (dry and wet) over the domain. The results were compared with the available ambient concentrations measured at PCD station (only 1 station with available data) in the Songkhla province. No acid deposition monitoring data in the SLB were available for comparison with modeling results. However, available data collected at different locations in Thailand appeared to be the same range as the model output. The model results showed that the maximum TS and TN deposition rate over the SLB area was quite high with the value of 2,853 and 4,448 eq/ha/year, respectively. The results approach the critical load of Sulfur for SLB area proposed by RAINS-Asia (1990) (500 eq/ha/year) and Milindekha (2001) (2,000 eq/ha/year), and critical load of Nitrogen proposed by Bouwman & Van Vuuren (1999) (2,150-2,850 eq/ha/year). Overall this may bring negative impacts to the surrounding environment including the soil and lake ecosystem. The values of water pH fluctuated seasonally due to rainfall. Hence further acid deposition onto the lake may also create problem for the lake ecosystem in certain periods of a year. The model results of acid deposition in the based year of 2010 should be improved with a more refined emission inventory. The modeling should be applied to assess impacts of emission scenarios, current and future, for investigation of the acid deposition and ambient air pollution in Southern Thailand. |
| Year | 2013 |
| 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) | Annachhatre, Ajit P.;Supat Wangwongwatnata; |
| Scholarship Donor(s) | Royal Thai Government Fellowship; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2013 |