TY  - JOUR
A1  - Ma, Jialiang
A1  - Ungeheuer, Florian
A1  - Zheng, Feixue
A1  - Du, Wei
A1  - Wang, Yonghong
A1  - Cai, Jing
A1  - Zhou, Ying
A1  - Yan, Chao
A1  - Liu, Yongchun
A1  - Kulmala, Markku
A1  - Daellenbach, Kaspar Rudolf
A1  - Vogel, Alexander L.
T1  - Nontarget screening exhibits a seasonal cycle of PM2.5 organic aerosol composition in Beijing
T2  - Environmental Science & Technology
N2  - 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.
Y1  - 2022
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/74998
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-749989
SN  - 1520-5851
SN  - 0013-936X
VL  - 56
IS  - 11
SP  - 7017
EP  - 7028
PB  - American Chemical Society
CY  - Columbus, Ohio
ER  -