Particle Size Distribution of Perfluoroalkyl Substances in Atmospheric Particulate Matter in Beijing

Abstract

BACKGROUND Anthropogenic emissions of persistent organic pollutants (POPs) tend to be concentrated in fine-level atmospheric particles. However, there are significant differences in the particle size distribution of perfluoroalkyl compounds (PFASs) in atmospheric particulate matter in different countries and regions, and the enrichment capacity of PFASs in different size particulate matter in Beijing is still unclear. OBJECTIVES To reveal the concentration level and particle size distribution characteristics of perfluoroalkyl substances in atmospheric particulate matter in Beijing, by collecting samples using a five stage impactor sampler and to discuss the effects of atmospheric particulate matter concentration changes on the concentration of perfluoroalkyl substances under different sizes. METHODS The samples were pretreated by ultrasonic extraction, and the concentrations of PFASs were determined by High Performance Liquid Chromatography-Electrospray Negative Ionization Source Tandem Mass Spectrometry. RESULTS The concentrations of ∑PFASs are 10.1-62.9 pg/m3, and 76.4%-83.8% of PFASs are concentrated in PM2.5. PFOA, PFNA and PFDA have the highest concentration in the <0.25 μm particles, accounting for 26.3%-43.7%, 30.3%-68.6% and 30.6%-49.7%, respectively. PFOS is not detected in the fine particles (0.25 μm) and 68.9%-2.8% of PFOS are concentrated in the particles with sizes of 0.25-1 μm and 1-2.5 μm. CONCLUSIONS The ∑PFASs in the atmospheric particles of smog in Beijing are 3.5 times that of sunny days, and the changes of atmospheric particle concentration of different particle sizes show different enrichment ability for each compound of PFASs, among which PFOA, PFOS, PFNA and PFDA middle chain PFASs are enriched more easily.

Keywords

• perfluoroalkyl substances
• atmospheric particulates
• pm2.5
• particle size distribution
• accumulation capacity