Characterization of Fe-containing particles in Chengdu, southwest China, using single-particle aerosol mass spectrometry

Single-particle aerosol mass spectrometry was used to study the characteristics of Fecontaining particles during winter in Chengdu, southwest China. The mass concentrations of PM 2.5 and PM 10 during the study period were 64 f 38 and 89 f 49 pg/m 3 , respectively, and NO 2 and particulate matter were high compared with most other regions of China. The Fecontaining particles were divided into seven categories with different mass spectra, sources and aging characteristics. The highest contribution was from Fe mixed with carbonaceous components (Fe-C, 23.1%) particles. Fe was more mixed with sulfate than nitrate and therefore the contribution of Fe mixed with sulfate (Fe-S, 20.7%) particles was higher than that of Fe mixed with nitrate (Fe-N, 12.5%) particles. The contributions from Fe-containing particles related to primary combustion were high in the small particle size range, whereas aged Fecontaining particles and dust-related particles were mostly found in the coarse particle size range. The air masses mainly originated from the west and east of Chengdu, and the corresponding PM 2.5 concentrations were 79 f 36 and 55 f 36 pg/m 3 , respectively. The west and east air masses showed stronger contributions of Fe-containing particles related to biomass burning (Fe-B) and fossil fuel combustion (Fe-C and Fe-S) particles, respectively. The southwest area contributed the most Fe-containing particles. Future assessments of the effects of Fe-containing particles during heavy pollution period should pay more attention to Fe-C and Fe-S particles. Emission-reduction of Fe-containing particles should consider both local emissions and short-distance transmission from the surrounding areas. (c) 2023 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.