Health assessment of emerging persistent organic pollutants (POPs) in PM2.5 in northern and central Taiwan

Over the last two decades, Taiwan has effectively diminished atmospheric concentrations of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) through the adept utilization of advanced technologies and the implementation of air pollution control devices. Despite this success, there exists a dearth of data regarding the levels of other PM2.5-bound organic pollutants and their associated health risks. To address this gap, our study comprehensively investigates the spatial and seasonal variations, potential sources, and health risks of PCDD/Fs, Polychlorinated biphenyls (PCBs), and Polychlorinated naphthalene (PCNs) in Northern and Central Taiwan. Sampling collections were conducted at three specific locations, including six municipal waste incinerators in Northern Taiwan, as well as a traffic and an industrial site in Central Taiwan. As a result, the highest mean values of PM2.5 (20.3–39.6 μg/m3) were observed at traffic sites, followed by industrial sites (14.4–39.3 μg/m3), and the vicinity of the municipal waste incinerator (12.4–29.4 μg/m3). Additionally, PCDD/Fs and PCBs exhibited discernible seasonal fluctuations, displaying higher concentrations in winter (7.53–11.9 and 0.09–0.12 fg I-TEQWHO/m3) and spring (7.02–13.7 and 0.11-0.16 fg I-TEQWHO/m3) compared to summer and autumn. Conversely, PCNs displayed no significant seasonal variations, with peak values observed in winter (0.05–0.10 fg I-TEQWHO/m3) and spring (0.03–0.08 fg I-TEQWHO/m3). Utilizing a Positive Matrix Factorization (PMF) model, sintering plants emerged as the predominant contributors to PCDD/Fs, constituting 77.9% of emissions. Woodchip boilers (68.3%) and municipal waste incinerators (21.0%) were identified as primary contributors to PCBs, while municipal waste incinerators (64.6%) along with a secondary copper and a copper sludge smelter (22.1%) were the principal sources of PCNs. Moreover, the study specified that individuals aged 19–70 in Northern Taiwan and those under the age of 12 years in Central Taiwan were found to have a significantly higher cancer risk, with values ranging from 9.26 x 10−9-1.12 x 10−7 and from 2.50 x 10−8-2.08 x 10−7respectively. [Display omitted] •In 20 years, ambient PCDD/Fs levels dropped from 63.8 to 6.99 fg I-TEQ/m3.•The traffic sites recorded the highest mean values of PM2.5 (20.3–39.6 μg/m3).•No significant variations in PCN levels were found among different seasons.•PCDD/Fs (TEQ) were predominantly in the particle phase in winter than PCBs and PCNs.•PC