Characteristics, main sources, health risks of PM_2.5-bound perfluoroalkyl acids in Zhengzhou, central China: From seasonal variation perspective

Abstract. Perfluoroalkyl acids (PFAAs) have become the focus due to their physicochemical stability and potential toxicity. In this study, the investigation aimed to characterize the pollution levels, identify the primary sources, and assess the health risks associated with PFAAs in PM_2.5. The average concentration range for PFAAs were between 46.68 and 181.63 pg·m^-3, with the main components being perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorobutanoic acid. PFAA concentrations in PM_2.5 were greatly influenced by the short- and medium-range air masses, and markedly elevated by industrial activities in surrounding urban areas. The results by positive matrix factorization revealed that PFOA-based products (38.2 %) and degradation byproducts of fluorotelomer alcohols (26.7 %) were the predominant sources. The average daily inhalation of 17 PFAAs fluctuated greatly (median: 4.35 × 10^-3 to 8.78 pg·(kg·d)^-1), showing different seasonal variations with estimated daily intake of PFOA and PFOS reaching peak value in winter (5869.39 pg) and spring (4219.41 pg), respectively. The research indicated that seasonal regulation of PFOA-related manufacturing and joint pollution control with neighboring cities could reduce PFAAs levels in PM_2.5. The results provided theoretical support for government to make targeted control plans for PFAAs and basic data for relevant researchers.