Nontarget screening exhibits a seasonal cycle of PM2.5 organic aerosol composition in Beijing

  • The molecular composition of atmospheric particulate matter (PM) in the urban environment is complex, and it remains a challenge to identify its sources and formation pathways. Here, we report the seasonal variation of the molecular composition of organic aerosols (OA), based on 172 PM2.5 filter samples collected in Beijing, China, from February 2018 to March 2019. We applied a hierarchical cluster analysis (HCA) on a large nontarget-screening data set and found a strong seasonal difference in the OA chemical composition. Molecular fingerprints of the major compound clusters exhibit a unique molecular pattern in the Van Krevelen-space. We found that summer OA in Beijing features a higher degree of oxidation and a higher proportion of organosulfates (OSs) in comparison to OA during wintertime, which exhibits a high contribution from (nitro-)aromatic compounds. OSs appeared with a high intensity in summer-haze conditions, indicating the importance of anthropogenic enhancement of secondary OA in summer Beijing. Furthermore, we quantified the contribution of the four main compound clusters to total OA using surrogate standards. With this approach, we are able to explain a small fraction of the OA (∼11–14%) monitored by the Time-of-Flight Aerosol Chemical Speciation Monitor (ToF-ACSM). However, we observe a strong correlation between the sum of the quantified clusters and OA measured by the ToF-ACSM, indicating that the identified clusters represent the major variability of OA seasonal cycles. This study highlights the potential of using nontarget screening in combination with HCA for gaining a better understanding of the molecular composition and the origin of OA in the urban environment.

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Author:Jialiang MaORCiD, Florian UngeheuerORCiDGND, Feixue Zheng, Wei Du, Yonghong WangORCiD, Jing Cai, Ying Zhou, Chao Yan, Yongchun LiuORCiDGND, Markku KulmalaORCiDGND, Kaspar Rudolf DaellenbachGND, Alexander L. VogelORCiDGND
URN:urn:nbn:de:hebis:30:3-749989
DOI:https://doi.org/10.1021/acs.est.1c06905
ISSN:1520-5851
ISSN:0013-936X
Parent Title (English):Environmental Science & Technology
Publisher:American Chemical Society
Place of publication:Columbus, Ohio
Document Type:Article
Language:English
Date of Publication (online):2022/03/18
Date of first Publication:2022/03/18
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2023/08/02
Volume:56
Issue:11
Page Number:12
First Page:7017
Last Page:7028
HeBIS-PPN:512570221
Institutes:Geowissenschaften / Geographie / Geowissenschaften
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - CC BY-NC-ND - Namensnennung - Nicht kommerziell - Keine Bearbeitungen 4.0 International