ABSTRACT
Exposure to high concentrations of fine particles (PM2.5) with toxic metals can have significant health effects, especially during the Chinese spring festival (CSF), due to the large amount of fireworks' emissions. Few studies have focused on the potential health impact of PM2.5 pollution in small cities in China during the 2020 CSF, which coincided with the COVID-19 outbreak that posed a huge challenge to the environment and obvious health issues to countries around the world. We examined the characteristics of PM2.5, including carbonaceous matter and elements, for three intervals during the 2020 CSF in Taizhou, identified the sources and evaluated the health risks, and compared them with those of 2018. The results showed that PM2.5 increased by 13.20% during the 2020 CSF compared to those in the 2018 CSF, while carbonaceous matter (CM) and elements decreased by 39.41% and 53.84%, respectively. The synergistic effects of emissions, chemistry, and transport may lead to increased PM2.5 pollution, while the lockdown measures contributed to the decrease in CM and elements during the 2020 CSF. Fe, Mn, and Cu were the most abundant elements in PM2.5 in both years, and As and Cr(VI) should be of concern as their concentrations in both years exceeded the NAAQS guideline values. Industry, combustion, and mineral/road dust sources were identified by PCA in both years, with a 5.87% reduction in the contribution from industry in 2020 compared to 2018. The noncarcinogenic risk posed by As, Co, Mn, and Ti in 2018 and As and Mn in 2020 was significant. The carcinogenic risk posed by As, Cr(VI), and Pb exceeded the accepted precautionary limit (1 ×10-6) in both years. Mn was the dominant contributor to the total noncarcinogenic risks, while Cr(VI) showed the largest excessive cancer risks posed by metals in PM2.5, implying its associated source, industry, was the greatest risk to people in Taizhou after exposure to PM2.5. Despite the increase in PM2.5 mass concentration, the health impacts were reduced by the lockdown policy implemented in Taizhou during the 2020 CSF compared to 2018. Our study highlights the urgent need to consider the mitigation of emissions in Taizhou and regional joint management efforts based on health protection objectives despite the rough source apportionment by PCA.