Peatland fires in Peninsular Malaysia act as primary source of dioxins, dioxin-like polychlorinated biphenyl, and particulate matter

The emissions of polyhalogenated aromatic hydrocarbons released in the air from peatland fires pose significant environmental health hazards. The contribution of peatland fires to environmental pollution is increasing continually in Malaysia. The composition of the smoke emerging from such fires plays a pivotal role in elucidating health risks. Therefore, the polyhalogenated aromatic hydrocarbon congeners must be assessed in the released smoke. The present study focused on two peatland forests in Peninsular Malaysia, comprising the active burning sites: Kuala Langat in Selangor and Pekan in Pahang. The smoke samples from the burning and burning-suppressed sites were analyzed for polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) particle number concentration (PNC) and particulate mass (PM) concentration. In the current study, we found hazardous levels of PCDD/Fs/dl-PCBs TEQ as high as 80.74 fg/m3 during the burning and 1,2,3,4,6,7,8-HpCDF (as high as 23.38 pg) and PCB-126 (as high as 34.41 pg) as the predominant congeners in the smoke, respectively. The smoke analysis of peatland fires revealed a significantly higher concentration of PNC and PM mass compared to a non-fire day. The analysis of the hourly PM ratios revealed fine particles as the dominant component in the ambient air during the peatland fires and non-fire days, indicating a strong association between PM mass and PNC. Thus, the present study establishes that peatland fires pose a significant health hazard, emphasizing the need for site-specific profiling of smoke constituents for effective management of health hazards.