Atmospheric deposition fluxes of selected air pollutants onto surface water and land in a tropical climate | |
| Author | Arika Bridhikitti |
| Call Number | AIT Thesis no.EV-04-04 |
| Subject(s) | Air--Pollution Atmospheric deposition |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. EV-04-04 |
| Abstract | The study on atmospheric deposition of particulate matter and associated semivolatile organic compounds and ionic substances were conducted on different characteristic sites in the Bangkok Metropolitan Region (BMR), Thailand during the dry period (February-mid May, 2004). In this study, two major tasks, determination the fluxes and estimation their deposition velocities, were carried out. The dry deposition flux was measured with direct measurement using a L-Apezion grease coated Mylar as a particle retainer. Mean mass fluxes were in the range of 50 to 87 mg/m2 - day with the highest flux found in urban-land. The overall PCBs fluxes sampled at 3 m above ground were between 30 and 160 ng/m2-day and Organochlorine Pesticides (OCPs) fluxes were 20-50 ng/m2-day. The total PAHs fluxes fluctuated between 280 and 13,000 ng/m2 -day, with the minimum P AHs flux found in suburban-water site and maximum in polluted urban land. Average dry deposition fluxes of individual particulate ionic species fluctuated in a wide range between 0.02 and 10 mg/ m2 -day depending on the species. The minimum fluxes associated with PM were found for ammonium and maximum for calcium ions. The deposition velocity (V ct) of species associated with PM was calculated from the measured particulate phase fluxes and their airborne concentration. The airborne concentrations were obtained from the filters of the PM2000 Ambient Eight-Stage Cascade Impactor with constant volume air sampling rate (28.3 alpm). Both fluxes and concentration were measured at 3 m. above ground level to avoid the turbulence at ground surface. The deposition velocities are similar between total PCBs and total OCPs compounds but different between these two species and P AHs. The deposition velocity of particulate airborne P AHs tended to be minimum on water surface area where the particulate PCBs and OCPs have maximum deposition velocity. The deposition velocities of all semi-VOCs onto urban land were higher than suburban land about 1.5-10 times. The calculated deposition velocities of the ionic species for all sampling sites were mostly in the range of 0.5-0.8 cm/s for Na+, about 0.3 emfs for NH/, 0.8-1.0 cm/s for K+, 1.1-1.5 cm/s for Mg2 \ 2.2-3.4 cm/s for Ca2+, 1.0-1.7 cm/s for Cr, 0.3-1.0 cm/s for N03- and 0.3- 0.5 cm/s for so/-. For V d of PM in different size ranges, mass percentage of the collected particles onto dry deposition plates were estimated based on number of particles counted under the Scanning Electron Microscopy (SEM). The values then were used to estimate V d for PM of different size ranges. The deposition velocities observed at the water surface site tended to decrease with the decreasing of the particle size. For the land site, the results showed a minimum mass deposition velocity with the diameter between 0.7 and l.lμm which is in a good agreement with results obtained by other studies using the same technique. |
| Year | 2004 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. EV-04-04 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Nguyen Thi Kim Oanh |
| Examination Committee(s) | Preeda Parkpian; Shim, Shang-Gyoo; Hathairatana Garivait |
| Scholarship Donor(s) | Her Majesty the Queen of Thailand |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2004 |