Characteristics and sources of peroxyacetyl nitrate in Hefei

In order to investigate the pollution characteristics and sources of peroxyacetyl nitrate (PAN) in Hefei, this study employed a continuous observation of PAN for one year at the super station of Hefei High-tech Zone from December 2023 to November 2024. The result showed that the average annual concentration of PAN in Hefei during the observe period was (0.81±0.60)×10−9, and the seasonal concentration ranked in autumn (1.22±0.76)×10−9> winter (0.80±0.52)×10−9> spring (0.72±0.37)×10−9> summer (0.48±0.38)×10−9. Diural concentration of PAN had single peak characteristics, with higher concentration during 12:00 to 17:00, and lower concentration during 1:00 to 8:00. The correlation of PAN and O3 was strongest in summer (R2=0.46) and the weakest in winter (R2=0.08), and the PAN/O3 in summer was 0.0176. PAN’s ambient age was longest in winter (133.0 h) and shortest in summer (1.3 h). Weighted potential source contribution function analysis showed that PAN in Hefei mainly comes from the local area in spring, and was formatted in local joint areas in autumn. This study reveals the pollution characteristics and main sources of PAN in Hefei, and provides a scientific basis for the prevention and control of photochemical pollution.