A thesis submitted in partial fulfillment of the requirements for the degree in Master of Engineering, School of Environment, Resources and Development

Thesis (M.Eng.) - Asian Institute of Technology, 2001

Persistent organochlorine pesticides (POCP) in the atmosphere of Bangkok Metropolitan Region (BMR) were investigated using two different sampling methods, active and passive. The active method uses the Anderson-type low volume sampler and the passive method uses the semi-permeable membrane device (SPMD). The former could trap POCP both in the gaseous and particulate phases while the latter could sequester only the gaseous phase. Samples were collected during the rainy season from three ambient air quality monitoring stations managed and operated by the Pollution Control Department in BMR; namely: Din Daeng representing urban area; Bangkok University, semi-urban/rural area; and Bang Na, residential/industrial mixed area. Analysis was done for 16 POCP following USEPA T0-4A method (for active) and SPMD Analytical Guide (for passive) using GC/ECD. Results of the investigation show that, even in rainy season, the BMR atmosphere is contaminated with traces of POCP, ranging from less than ng/m3 to a few ng/m3 . Most of the POCP were present in the gaseous form. Between the two methods use, the active yielded satisfactory results since it trapped more POCP than SPMD. Hence, it is recommended for use in the tropical conditions. The potential of SPMD as an alternative method could not be negated, especially if calibrated uptake rates specific for POCP could be established. Its main advantage over the other method is that it can be deployed even in remote areas where electricity is lacking.