Concentrations, sources and health risks of per- and polyfluoroalkyl substances in ambient PM1 in the Pearl River Delta region, China

Most studies focus on per- and polyfluoroalkyl substances (PFAS) concentrations in dust or particle phase, leaving PFAS in PM₁ particles in urban areas poorly understood. This study investigated PFAS levels and sources in ambient PM₁ from 94 primary and secondary schools across six cities in the Pearl River Delta (PRD) during October to December 2018. We analyzed 32 PFAS compounds in PM₁, with total PFAS levels at 58.92 pg/m³, ranging from 7.33 to 341.77 pg/m³. Perfluoroalkyl sulfonic acids (PFSAs) dominated (median: 38.85 pg/m³), followed by perfluoroalkyl carboxylic acids (PFCAs, median: 11.92 pg/m³), alternatives (median: 1.24 pg/m³), and perfluoroalkyl acid (PFAA) precursors (median: 0.29 pg/m³). The main source for PFAS was organic synthesis industries (47.91 %). Air masses originated from southern China, the east coast, and the South China Sea. PFAS showed positive correlations with cations and anions. Health risk assessment using estimated daily intake (EDI) and hazard quotient (HQ) found very low inhalation risk (HQ < 1). Our results highlight pollution from local industrial production and the eastern coastal areas as being the primary contributor to airborne PFAS in PRD schools. Elevated PFAS levels in PM₁ present potential health risks, and their interactions with other pollutants in PM₁ reflect their complex origins and behaviors.