Spatial-temporal variability and heath impact of particulate matter during a 2019-2020 biomass burning event in Southeast Asia.

To understand the characteristics of particulate matter (PM) in the Southeast Asia region, the spatial-temporal concentrations of PM10, PM2.5 and PM1 in Malaysia (Putrajaya, Bukit Fraser and Kota Samarahan) and Thailand (Chiang Mai) were determined using the AS-LUNG V.2 Outdoor sensor. The period of measurement was over a year from 2019 to 2020. The highest concentrations of all sizes of PM in Putrajaya, Bukit Fraser and Kota Samarahan were observed in September 2019 while the highest PM10, PM2.5 and PM1 concentrations in Chiang Mai were observed between March and early April 2020 with 24 h average concentrations during haze days in ranges 83.7-216 µg m-3, 78.3-209 µg m-3 and 57.2-140 µg m-3, respectively. The average PM2.5/PM10 ratio during haze days was 0.93 ± 0.05, which was higher than the average for normal days (0.89 ± 0.13) for all sites, indicating higher PM2.5 concentrations during haze days compared to normal days. An analysis of particle deposition in the human respiratory tract showed a higher total deposition fraction value during haze days than on non-haze days. The result from this study indicated that Malaysia and Thailand are highly affected by biomass burning activity during the dry seasons and the Southwest monsoon.

Emission of dioxins/furans and other U-POPs from test burns of non-POP pesticides in a hazardous waste incinerator.

This paper presents the results of test burns for obsolete pesticides (OPs) of the permethrin group in a high temperature incinerator (HTI) in Southeast Asia. Three test burn runs were conducted, a baseline run when no OP was fed to the incinerator, and two test runs with different mixtures of OP compounds (formula 1 and 2, refer to Table 1 for detail) containing chlorine in the feeding wastes. The unintentional formed persistent organic pollutants (U-POPs) including 17 dioxins/furans, 12 dioxin-like PCBs and 12 chlorobenzenes (CBs) were monitored in all input materials and all discharges (flue gas, scrubbing liquid and solid residues). The results show relatively high levels of the U-POPs in the flue gas emission with total dioxins/furans of 4.4, 3.4, and 8.4 ng I-TEQ/m(3) in the baseline, test run 1 and test run 2, respectively, which are above international acceptable emission levels. The PCB levels in flue gas were, respectively, 0.01, 0.3 and 0.4 ng I-TEQ/m(3). The baseline thus had similar U-POPs levels with the OP test runs. In stack emission, approximately 90% of the U-POPs and 100% of CBs were present in gas phase. The emission factors, mass of pollutants per metric ton (tonne) of input waste, of U-POPs associated with fly ash (from bag house) were the highest, followed by flue gas and bottom ash while those associated with scrubbing liquid were relatively low. Among the waste input material only the black toner power contained U-POPs, but at low levels. The profiles of the dioxins/furans and PCBs in the toner waste were significantly different from that in the discharges. Despite the overall good destruction and removal efficiency of permethrin (better than 90%) the high emission of U-POPs and CBs from the test burn is of another more serious concern. To our best knowledge the findings of this study are the first of this kind for the Southeast Asia. The findings emphasize that if not properly conducted a standard destruction technology of a non-POP chemical can lead to a release of a range of more dangerous U-POPs into the environment.