Chemical Evolution of Secondary Organic Aerosol Tracers during High-PM2.5 Episodes at a Suburban Site in Hong Kong over 4 Months of Continuous Measurement
Qiongqiong Wang, Shan Wang, Yuk Ying Cheng, Hanzhe Chen, Zijing Zhang, Jinjian Li, Dasa Gu, Zhe Wang, and Jian Zhen Yu
Atmospheric Chemistry and Physics, 2022, 22, 11239-11253. Link>>
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Enhanced SOA formation during PM2.5 episodes, especially in the summer and the early fall episodes.
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The SOA chemical evolution characteristics during PM2.5 episodes vary by precursor and by season.
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The
necessity to apply high-time-resolution organic marker measurement at
multiple sites to fully capture the spatial heterogeneity of haze
pollution at the city scale was suggested.
Estimating Primary Vehicular Emissions Contributions to PM2.5
using the Chemical Mass Balance Model: Accounting for Gas-Particle
Partitioning of Organic Aerosols and Oxidation Degradation of Hopanes
Yee Ka Wong, X. H. Hilda Huang, Yuk Ying Cheng, and Jian Zhen Yu
Environmental Pollution, 2021, 118131. Link>>
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Gas-particle partitioning of organic aerosols and hopane oxidation severely bias CMB estimation of primary vehicular PM2.5 contributions.
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CMB
accounting for these effects apportions one third less and 3 times
higher contributions by diesel and gasoline vehicles, respectively.
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The new gasoline-diesel split in primary vehicular PM2.5 contributions is significantly different from that by traditional CMB.
Ambient
Measurements of Heterogeneous Ozone Oxidation Rates of Oleic, Elaidic,
and Linoleic Acid using a Relative Rate Constant Approach in an Urban
Environment
Qiongqiong Wang and Jian Zhen Yu
Journal of Geophysical Research - Atmosphere, 2021, e2021GL095130. Link>>
Oleic
and linoleic acid are among the major components in cooking-emitted
particles. Their degradation via heterogeneous reactions with
atmospheric oxidants modifies the aerosol compositions and properties,
altering the aerosols' climate impact. We succeeded in determining the
decay rate constants of three cooking molecules (i.e., oleic, elaidic,
and linoleic acid) by taking advantage of their bihourly measured
concentrations at an urban location. The estimated lifetime of oleic
acid was 6 h under conditions of ∼12 ppb ozone and 60%–100% relative
humidity encountered at our urban location or an inferred ∼2 h at a
higher ozone level of ∼40 ppb. This work provides the first kinetic
data pertaining to real-world conditions.
Hourly
Measurements of Organic Molecular Markers in Urban Shanghai, China:
Primary Organic Aerosol Source Identification and Observation of
Cooking Aerosol Aging
Qiongqiong Wang, Xiao He, Min Zhou, Dan Dan Huang, Liping Qiao, Shuhui Zhu, Ying-ge Ma, Hong-li Wang, Li Li, Cheng Huang, X. H. Hilda Huang, Wen Xu, Douglas Worsnop, Allen H. Goldstein, Hai Guo, and Jian Zhen Yu
ACS Earth & Space Chemistry, 2020, 4, 1670-1685. Link>>
We
deployed a thermal desorption aerosol gas chromatography−mass spectrometry
(TAG) system at an urban location in Shanghai for three weeks in Nov. 2018. We
have 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.
Hourly
Measurements of Organic Molecular Markers in Urban Shanghai, China:
Observation of Enhanced Formation of Secondary Organic Aerosol during
Particulate Matter Episodic Periods
Xiao He, Qiongqiong Wang, X. H. Hilda Huang, Dan Dan Huang, Min Zhou, Liping Qiao, Shuhui Zhu, Ying-ge Ma, Hong-li Wang, Li Li, Cheng Huang, Wen Xu, Douglas R. Worsnop, Allen H. Goldstein, and Jian Zhen Yu Atmospheric Environment, 2020, 240, 117807. Link>>
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Online measurement of individual aerosol organics was made for the first time in urban Shanghai.
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Significant mass enhancement of SOA tracers and nitrate was observed during five PM2.5 episodes.
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Toluene SOA tracer had a mass increment of 5.6 during episodes vs. <2 for primary pollutants.
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The diagnostic ratio of two α-pinene SOA tracers suggested fresh SOA in urban Shanghai.
Source Apportionment of PM2.5 in Shanghai based on Hourly Organic Molecular Markers and other Source Tracers
Rui Li, Qiongqiong Wang, Xiao He, Shuhui Zhu, Kun Zhang, Yusen Duan, Qingyan Fu, Liping Qiao, Yangjun Wang, Li Huang, Li Li, and Jian Zhen Yu Atmospheric Chemistry & Physics, 2020, 20, 12047-12061. Link>>
A source apportionment study was carried out through utilizing hourly measured PM2.5
and its chemical components, including organic molecular markers. The
PMF receptor modeling has resolved 11 source factors, among which 3
organics-dominated factors, namely an SOA factor, biomass burning, and
cooking factor, were resolved from other sources due to the
availability of the organic marker data.
Tracer-based Characterization of Source Variations of PM2.5 and Organic Carbon in Shanghai Influenced by the COVID-19 Lockdown
The
lockdown in the middle of COVID-19 outbreak brought about steep
reductions in pollution activities. We seized this unique opportunity
to study air pollution chemistry. Our comprehensive measurements of PM2.5
chemical composition has revealed the nonlinear response of secondary
pollutants to reductions in broad primary precursor pollutants. This
work provides quantitative data and insights for future development of
control strategies in megacities.
