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Download fileMolecular Characterization and Source Identification of Atmospheric Particulate Organosulfates Using Ultrahigh Resolution Mass Spectrometry
journal contribution
posted on 2019-05-14, 00:00 authored by Kai Wang, Yun Zhang, Ru-Jin Huang, Meng Wang, Haiyan Ni, Christopher J. Kampf, Yafang Cheng, Merete Bilde, Marianne Glasius, Thorsten HoffmannOrganosulfates
(OSs) have been observed as substantial constituents
of atmospheric organic aerosol (OA) in a wide range of environments;
however, the chemical composition, sources, and formation mechanism
of OSs are still not well understood. In this study, we first created
an “OS precursor map” based on the elemental composition
of previous OS chamber experiments. Then, according to this “OS
precursor map”, we estimated the possible sources and molecular
structures of OSs in atmospheric PM2.5 (particles with
aerodynamic diameter ≤ 2.5 μm) samples, which were collected
in urban areas of Beijing (China) and Mainz (Germany) and analyzed
by ultrahigh-performance liquid chromatography (UHPLC) coupled with
an Orbitrap mass spectrometer. On the basis of the “OS precursor
map”, together with the polarity information provided by UHPLC,
OSs in Mainz samples are suggested to be mainly derived from isoprene/glyoxal
or other unknown small polar organic compounds, while OSs in Beijing
samples were generated from both isoprene/glyoxal and anthropogenic
sources (e.g., long-chain alkanes and aromatics). The nitrooxy-OSs
in the clean aerosol samples were mainly derived from monoterpenes,
while much fewer monoterpene-derived nitrooxy-OSs were obtained in
the polluted aerosol samples, showing that nitrooxy-OS formation is
affected by different precursors in clean and polluted air conditions.