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Highlighted Publications
Simultaneous Determination of Aerosol Inorganic and Organic Nitrogen by Thermal Evolution and Chemiluminescence Detection

Xu Yu, Qianfeng Li, Yao Ge, Yumin Li, Kezheng Liao, X. H. Hilda Huang, Jinjian Li, and Jian Zhen Yu
Environmental Science & Technology, 2021, 55, 11579-11589. Link>>
  • Inorganic nitrogen (IN) and organic nitrogen (ON) molecules constitute a significant part of atmospheric aerosol. Unlike IN, the total ON quantity remains largely unquantified due to a lack of simple and direct measurement method.
  • We developed an analyzer system that utilizes programmed thermo-evolution of carbonaceous and nitrogenous aerosols and chemiluminescent detection coupled with multivariate curve resolution data treatment to achieve simultaneous quantification of IN and ON.
  • This method breakthrough opens the door to quantifying an important pool of aerosol N that was analytically inaccessible in the past.

Chemical Synthesis of Muultifunctional Air Pollutants: Terpene-Derived Nitrooxy Organosulfates

Yuchen Wang, Rongbiao Tong, and Jian Zhen Yu
Environmental Science & Technology, 2021, 55, 8573-8582. Link>>
We succeed in first synthesis of terpene-derived nitrooxy organosulfates, providing indispensable standards to study multifunctional air pollutants formed between anthropogenic pollution and natural emissions. The availability of the authentic standards allows us to clarify previous misidentification and reveals the compound-specific propensity of carbon skeleton rearrangements for terpene-derived nitrooxy organosulfates during atmospheric oxidation.

Environmental Advances online platform:

Tracer-based Chracterization of Source Variations of PM2.5 and Organic Carbon in Shanghai Influenced by the COVID-19 Lockdown

Shuhui Zhu, Qiongqiong Wang, Liping Qiao, Min Zhou, Shan Wang, Shengrong Lou, Dandan Huang, Qian Wang, Shengao Jing, Hongli Wang, Changhong Chen, Cheng Huang, and Jian Zhen Yu
Faraday Discussions, 2021, 226, 112-137. Link>>

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.)

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>>

  • Online measurement of individual aerosol organics was made for the first time in urban Shanghai.
  • Significant mass enhancement of SOA tracers and nitrate was observed during five PM2.5 episodes.
  • Toluene SOA tracer had a mass increment of 5.6 during episodes vs. <2 for primary pollutants.
  • 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.

Tracking Separate Contributions of Diesel and Gasoline Vehicles to Roadside PM2.5 through Online Monitoring of Volatile Organic Compounds and PM2.5 Organic and Elemental Carbon: a 6-year Study in Hong Kong

Yee Ka Wong, X. H. Hilda Huang, Peter K. K. Louie, Alfred L. C. Yu, Damgy H. L. Chan, and Jian Zhen Yu
Atmospheric Chemistry & Physics, 2020, 20, 9871-9882. Link>>

Knowledge of the relative contribution of gasoline versus diesel powered vehicles to fine particulate matter is highly policy relevant and yet there lacks an effective observation-based method to determine this quantity, especially for its robust tracking over a period of years. In this work, we present an approach to track separate contributions by gasoline and diesel vehicles through positive matrix factorization analysis of online monitoring data (VOCs, OC and EC) measurable by relatively inexpensive analytical instruments.

Abundance and Sources of Benzo[a]pyrene and other PAHs in Ambient Air in Hong Kong: A Review of 20-year Measurements (1997-2016)

Kezheng Liao and Jian Zhan Yu
Chemosphere, 2020, 259, 127518. Link>>

  • Benzo[a]pyrene decreased at the rate of 0.013 ng/m3/year during 1998-2016.
  • Other 5-6 ring PAHs show similar declining trends.
  • Major sources of PAHs are biomass burning, coal combustion and vehicular exhaust.
  • Reductions in emission amounts of these sources have led to the declines in PAH levels.

Assessment of Interactions between Transition Metals and Atmospheric Organics: Ascorbic Acid Depletion and Hydroxyl Radical Formation in Organic-Metal Mixtures

Manfei Lin and Jian Zhen Yu
Environmental Science & Technology, 2020, 54, 1431-1442. Link>>

Transition metals and certain atmospheric organics are recognized to be redox active and responsible for inducing ROS in human cells. We report here the mixture effects of metals and organics on the measured OP in the presence of ascorbic acid (AA). This work reveals that carboxylic acids enhanced the OPAA and OP•OH by Cu2+ (or Fe2+) while imidazoles suppressed them. While ambient HULIS showed negligible impacts, two biomass burning source HULIS samples from rice straw and sugarcane leaf burning displayed unambiguous suppression or enhancement effect on OPAA and OP•OH by Cu2+ (or Fe2+). The effect was metal-specific and source HULIS-specific.

Efficient Control of Atmospheric Sulfate Production based on Three Formation Regimes

Jian Xue, Xin Yu, Zibing Yuan, Stephen M. Griffith, Alexis K. H. Lau, John H. Seinfeld, and Jian Zhen Yu
Nature Geoscience, 2019, 12, 977-982. Link>>

While the reactant-product link between sulfur dioxide and airborne sulfate formation is common knowledge, the complex oxidants and mechanisms that enable this transformation are not. This work describes the conceptual framework to delineate the relationship between sulfate and one set of its controllable precursors, nitrogen oxides (NOx), laying the groundwork for formulating more effective measures of reducing sulfate.

Source Apportionment of PM2.5 Using Hourly Measurements of Elemental Tracers and Major Constituents in an Urban Environment: Investigation of Time-Resolution Influence

Qiongqiong Wang, Liping Qiao, Min Zhou, Shuhui Zhou, Stephen Griffith, Li Li, and Jian Zhen Yu
Journal of Geophysical Research: Atmospheres, 2018, 123, 5284-5300. Link>>

Using actual field data, we unequivocally demonstrated the benefits of high-time resolution chemical composition data in tracking PM2.5 pollution. The improved robustness is achieved through better capturing of diurnal scale dynamics in source activities. Findings from this study provide implementable guidance for effective monitoring strategies

Abundance and Sources of Phthalic Acids, Benzene-Tricarboxylic Acids, and Phenolic Acids in PM2.5 at Urban and Suburban Sites in Southern China

Xiao He, X. H. Hilda Huang, Ka Shing Chow, Qiongqiong Wang, Ting Zhang, Dui Wu, and Jian Zhen Yu
ACS Earth & Space Chemistry, 2018, 2, 147-158.  Link>>

  • The four phenolic acids, all possessing partial lignin structures, are associated with biomass burning emissions. They serve as precursors leading to significant constituents of brown carbon.
  • The three BTCAs have a strong association with secondary formation origins. Structurally, the three BTCAs are among the logical oxidation products of PAHs and/or elemental carbon.
  • The three phthalic acids are moderately correlated with sulfate, levoglucosan, and a number of PAHs, indicating multiple significant sources.

Impact of Secondary Organic Aerosol Tracers on Tracer-Based Source Apportionment of Organic Carbon and PM2.5: A Case Study in the Pearl River Delta, China

Qiongqiong Wang, Xiao He, X. H. Hilda Huang, Stephen M. Griffith, Yongming Feng, Ting Zhang, Qingyan Zhang, Dui Wu, and Jian Zhen Yu
ACS Earth & Space Chemistry, 2017, 1, 562-571.  Link>>

  • SOC from specific precursors may have different formation pathways than secondary sulfate and nitrate formation processes, and their source contributions could not be properly resolved without the indicative tracers included in PMF.
  • This study demonstrates the utility of biogenic SOA tracers in resolving isoprene-derived SOA and highlights the need for more SOAtracers, especially those specific to anthropogenic precursors, in improving the source apportionment for those broad OA sources such as industrial emissions.

Synthesis of Four Monoterpene-Derived Organosulfates and Their Quantification in Atmospheric Aerosol Samples

Yuchen Wang, Jingyun Ren, X. H. Hilda Huang, Rongbiao Tong, and Jian Zhen Yu
Environmental Science & Technology, 2017, 51, 6791-6801.  Link>>

  • We report a unified synthesis strategy starting from the respective monoterpene through Upjohn dihydroxylationor Sharpless asymmetric dihydroxylation followed bymonosulfation with the sulfur trioxide-pyridine complex.
  • The in-house availability of the authentic standards enables us to discover that β-pinene OS, due to the sulfate group at the primary carbon, partially degrades to a dehydrogenated OS compound during LC/MS analysis and a hydroperoxy OS over a prolonged storage period (> 5 months) and forms a regioisomer through intermolecular isomerization.

Sulfate Formation Enhanced by a Cocktail of High NOx, SO2, Particulate Matter, and Droplet pH during Haze-Fog Events in Megacities in China: An Observation-Based Modeling Investigation

Jian Xue, Zibing Yuan, Stephen M. Griffith, Xin Yu, Alexis K. H. Lau, and Jian Zhen Yu
Environmental Science & Technology, 2016, 50, 7325-7334.  Link>>
  • At a typical haze-fogwater pH of 5.6, the most important pathway to be oxidation of S(IV) by dissolved NO2.
  • The unique cocktail of high fogwater pH, high concentrations of NO2, SO2, and PM, and small fog droplets are capable of greatly enhancing sulfate formation.
  • Insights gained on major contributing factors imply that reduction of road dust and NOx emissions could lessen PM2.5 loadings in Chinese megacities during fog events.

Organosulfates in Humic-like Substance Fraction Isolated from Aerosols at Seven Locations in East Asia: A Study by Ultra-High-Resolution Mass Spectrometry

Peng Lin, Jian Zhen Yu, Guenter Engling, and Markus Kalberer
Environmental Science & Technology, 2012, 46, 13118-13127.  Link>>

  • In HULIS fraction, OS containing 10 carbon atoms were the most abundant, indicating monoterpenes as important precursors of OS.
  • The double bond equivalent (DBE) values indicate the majority of OS (>90%) in the HULIS fraction are aliphatic.
  • The −ONO2 group is the more readily hydrolyzed than the −OSO3 group. There is a lack of evidence for the epoxide pathway to account for the formation of OS in the CHONS subgroup.