Assessment of particle-bound PFAS in ambient air from a coastal urban environment in South Florida

Per- and polyfluoroalkyl substances (PFAS) are man-made pollutants widely used in industrial and consumer products, known to pose significant health risks. While their occurrence in water, soil, and food has been extensively studied, limited research has focused on ambient air, particularly in the U.S. This study examines airborne PFAS collected outdoors at Florida International University's Biscayne Bay Campus (North Miami, FL) from January to December 2024. Atmospheric particulate matter (APM) was collected using a Tisch cascade impactor, which mimics the human respiratory system, and PFAS were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). PFBA was the most frequently detected compound (74 %), having the highest average concentration (52.8 pg/m³). PFOS and PFOA were detected in 30 % of samples, averaging 7.65 pg/m³ and 5.85 pg/m³, respectively. High temperature, high humidity and rainfall events favor the persistence of PFAS in airborne particles. PFBA and N-MeFOSE (detected in 70 % of samples) tended to adsorb onto coarse particles (> 2.1 µm), while PFOS exhibited a bimodal distribution, with a mode in fine particles (< 2.1 µm) associated with tracheobronchial and alveolar regions. This research highlights the importance of inhalation exposure studies to better assess the health impacts of airborne PFAS.