Unprecedented Ambient Sulfur Trioxide (SO3) Detection : Possible Formation Mechanism and Atmospheric Implications
Yao, Lei; Fan, Xiaolong; Yan, Chao; Kurtén, Theo; Daellenbach, Kaspar R.; Li, Chang; Wang, Yonghong; Guo, Yishuo; Dada, Lubna; Rissanen, Matti P.; Cai, Jing; Tham, Yee Jun; Zha, Qiaozhi; Zhang, Shaojun; Du, Wei; Yu, Miao; Zheng, Feixue; Zhou, Ying; Kontkanen, Jenni; Chan, Tommy; Shen, Jiali; Kujansuu, Joni T.; Kangasluoma, Juha; Jiang, Jingkun; Wang, Lin; Worsnop, Douglas R.; Petäjä, Tuukka; Kerminen, Veli Matti; Liu, Yongchun; Chu, Biwu; He, Hong; Kulmala, Markku; Bianchi, Federico (2020-11-10)
Yao, Lei
Fan, Xiaolong
Yan, Chao
Kurtén, Theo
Daellenbach, Kaspar R.
Li, Chang
Wang, Yonghong
Guo, Yishuo
Dada, Lubna
Rissanen, Matti P.
Cai, Jing
Tham, Yee Jun
Zha, Qiaozhi
Zhang, Shaojun
Du, Wei
Yu, Miao
Zheng, Feixue
Zhou, Ying
Kontkanen, Jenni
Chan, Tommy
Shen, Jiali
Kujansuu, Joni T.
Kangasluoma, Juha
Jiang, Jingkun
Wang, Lin
Worsnop, Douglas R.
Petäjä, Tuukka
Kerminen, Veli Matti
Liu, Yongchun
Chu, Biwu
He, Hong
Kulmala, Markku
Bianchi, Federico
10.11.2020
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202101151365
https://urn.fi/URN:NBN:fi:tuni-202101151365
Kuvaus
Peer reviewed
Tiivistelmä
Sulfur trioxide (SO3) is a crucial compound for atmospheric sulfuric acid (H2SO4) formation, acid rain formation, and other atmospheric physicochemical processes. During the daytime, SO3is mainly produced from the photo-oxidation of SO2by OH radicals. However, the sources of SO3during the early morning and night, when OH radicals are scarce, are not fully understood. We report results from two field measurements in urban Beijing during winter and summer 2019, using a nitrate-CI-APi-LTOF (chemical ionization-Atmospheric pressure interface-long-Time-of-flight) mass spectrometer to detect atmospheric SO3and H2SO4. Our results show the level of SO3was higher during the winter than during the summer, with high SO3levels observed especially during the early morning (05:00 to 08:30) and night (18:00 to 05:00 the next day). On the basis of analysis of SO2, NOx, black carbon, traffic flow, and atmospheric ions, we suggest SO3could be formed from the catalytic oxidation of SO2on the surface of traffic-related black carbon. This previously unidentified SO3source results in significant H2SO4formation in the early morning and thus promotes sub-2.5 nm particle formation. These findings will help in understanding urban SO3and formulating policies to mitigate secondary particle formation in Chinese megacities.
Kokoelmat
- TUNICRIS-julkaisut [18936]