Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans in the Urban Air of Kuala Lumpur and Their Health Risk Assessment
摘要
Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are persistent organic pollutants that can remain in the environment for a long time. This study quantified the concentrations of 17 PCDDs and PCDFs congeners in PM2.5, total suspended particles (TSP), the gaseous phase, and total ambient air (TSP + gaseous) at an urban roadside site in Kuala Lumpur, Malaysia, a densely populated tropical city influenced by traffic and other anthropogenic activities, and assessed the associated health risks. PM2.5 and TSP were collected on quartz microfibre filters using separate high-volume samplers, whereas the gaseous phase was captured on polyurethane foam. The results revealed that the total ambient concentration of Ʃ17PCDD + PCDF was 736 ± 375 fg WHO-TEQ m−3, whereas PM2.5, TSP, and gaseous phase concentrations were 223 ± 161 fg WHO-TEQ m−3, 337 ± 213 fg WHO-TEQ m−3 and 507 ± 273 fg WHO-TEQ m−3, respectively. Tetra-, penta-, and hexa-PCDDs/PCDFs contributed between 88 and 99% of the total TEQ concentrations, indicating that lower chlorinated congeners were the dominant contributors to overall toxicity. The Ʃ17PCDD + PCDF displayed a significant difference between gaseous and particle concentrations (p < 0.001). Health risk assessment indicated that exposure to the gaseous phase of Ʃ17PCDD + PCDF resulted in a higher estimated inhalation lifetime cancer risk (1.58E−06–5.28E−06) than exposure to the particulate phases of TSP (9.1E-07–3.0E-06) and PM2.5 (6.98E−07–2.33E−06), mainly due to the higher abundance of lower chlorinated congeners with greater toxic equivalency contributions in the gaseous phase. Our study highlights the importance of measuring both gaseous and particulate phases of PCDDs/PCDFs to improve the assessment of inhalation exposure risks in urban environments.
Graphical abstract