TY - JOUR
T1 - Hourly Measurements of Organic Molecular Markers in Urban Shanghai, China
T2 - Primary Organic Aerosol Source Identification and Observation of Cooking Aerosol Aging
AU - Wang, Qiongqiong
AU - He, Xiao
AU - Zhou, Min
AU - Huang, Dan Dan
AU - Qiao, Liping
AU - Zhu, Shuhui
AU - Ma, Ying Ge
AU - Wang, Hong Li
AU - Li, Li
AU - Huang, Cheng
AU - Huang, X. H.Hilda
AU - Xu, Wen
AU - Worsnop, Douglas
AU - Goldstein, Allen H.
AU - Guo, Hai
AU - Yu, Jian Zhen
N1 - Funding Information:
We are thankful for funding support from the National Key R&D Program of China (2018YFC0213800), the National Natural Science Foundation of China (41875161), the Hong Kong Research Grants Council (C5004-15E, 16305418, and R6011-18), and the Hong Kong University of Science & Technology (VPRDO19IP01).
Publisher Copyright:
Copyright © 2020 American Chemical Society.
PY - 2020/9/17
Y1 - 2020/9/17
N2 - Molecular markers in ambient organic aerosol (OA) provide highly specific source information. Their traditional quantification is based on offline analysis of filter samples, and the coarse time resolution and labor-intensive nature hugely limit the utility of the tracer data. In this study, hourly organic molecular markers in fine particulate matter were measured using a recently commercialized thermal desorption aerosol gas chromatography-mass spectrometry (TAG) technique at an urban location in Shanghai, China during a three-week campaign from 9 November to 3 December, 2018. Selected primary OA molecular markers, including anhydrosugars, fatty acids, aromatic acids, and polycyclic aromatic hydrocarbons (PAHs), were examined in detail. Their diurnal variations showed characteristic features representing the corresponding emission source activities. For example, stearic acid showed a clear peak around 7 pm, in accordance with the enhanced cooking activities during mealtime. Diagnostic ratios of related makers of different reactivities provided unique information in uncovering the source information and tracking evolution of the OA in the atmosphere, for example, ratios of levoglucosan to its isomers and K+ identified crop residue burning as the major form of biomass burning (BB). Ratios of unsaturated and saturated fatty acids gave unambiguous indication of atmospheric degradation of unsaturated fatty acids after emissions. Oleic acid to stearic acid ratios in ambient data (0.83 ± 0.54) were lower than those in the source profiles (1.2-6.5). Furthermore, the oleic acid to stearic acid ratio was found to be highly correlated with O/C ratios (Rp: -0.66), suggesting the possible utility of oleic acid as a model compound to examine the heterogeneous reaction of cooking-related OA. PAH ratio-ratio plots helped identify varying influences of major combustion sources associated with air masses of different origins, revealing that BB and coal combustion were dominant under the influence of long-range transport air mass, while vehicle emissions were dominant under local/median-range air mass influence. This study demonstrated the utility of high time-resolution organic markers in capturing the dynamic change of source emissions and atmospheric aging, providing observational evidence to support their use in source apportionment.
AB - Molecular markers in ambient organic aerosol (OA) provide highly specific source information. Their traditional quantification is based on offline analysis of filter samples, and the coarse time resolution and labor-intensive nature hugely limit the utility of the tracer data. In this study, hourly organic molecular markers in fine particulate matter were measured using a recently commercialized thermal desorption aerosol gas chromatography-mass spectrometry (TAG) technique at an urban location in Shanghai, China during a three-week campaign from 9 November to 3 December, 2018. Selected primary OA molecular markers, including anhydrosugars, fatty acids, aromatic acids, and polycyclic aromatic hydrocarbons (PAHs), were examined in detail. Their diurnal variations showed characteristic features representing the corresponding emission source activities. For example, stearic acid showed a clear peak around 7 pm, in accordance with the enhanced cooking activities during mealtime. Diagnostic ratios of related makers of different reactivities provided unique information in uncovering the source information and tracking evolution of the OA in the atmosphere, for example, ratios of levoglucosan to its isomers and K+ identified crop residue burning as the major form of biomass burning (BB). Ratios of unsaturated and saturated fatty acids gave unambiguous indication of atmospheric degradation of unsaturated fatty acids after emissions. Oleic acid to stearic acid ratios in ambient data (0.83 ± 0.54) were lower than those in the source profiles (1.2-6.5). Furthermore, the oleic acid to stearic acid ratio was found to be highly correlated with O/C ratios (Rp: -0.66), suggesting the possible utility of oleic acid as a model compound to examine the heterogeneous reaction of cooking-related OA. PAH ratio-ratio plots helped identify varying influences of major combustion sources associated with air masses of different origins, revealing that BB and coal combustion were dominant under the influence of long-range transport air mass, while vehicle emissions were dominant under local/median-range air mass influence. This study demonstrated the utility of high time-resolution organic markers in capturing the dynamic change of source emissions and atmospheric aging, providing observational evidence to support their use in source apportionment.
KW - atmospheric aging
KW - biomass burning
KW - cooking aerosol
KW - organic molecular markers
KW - primary organic aerosols
KW - source identification
KW - thermal desorption aerosol gas chromatography-mass spectrometry
UR - http://www.scopus.com/inward/record.url?scp=85089466896&partnerID=8YFLogxK
U2 - 10.1021/acsearthspacechem.0c00205
DO - 10.1021/acsearthspacechem.0c00205
M3 - Journal article
AN - SCOPUS:85089466896
SN - 2472-3452
VL - 4
SP - 1670
EP - 1685
JO - ACS Earth and Space Chemistry
JF - ACS Earth and Space Chemistry
IS - 9
ER -