Zhijun Wu

Xi'an Technological University

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Min Hu

State Key Joint Laboratory of Environment Simulation and Pollution Control

100

Song Guo

State Key Joint Laboratory of Environment Simulation and Pollution Control

Alfred Wiedensohler

Leibniz Institute for Tropospheric Research

Dongjie Shang

State Key Joint Laboratory of Environment Simulation and Pollution Control

Limin Zeng

Taiyuan University of Technology

Yusheng Wu

University of Helsinki

Yujue Wang

Shenyang Pharmaceutical University

Hartmut Herrmann

Leibniz Institute for Tropospheric Research

Laurent Poulain

Leibniz Institute for Tropospheric Research

W. Birmili

German Environment Agency

Cooperative Institutions

Peking University

208

State Key Joint Laboratory of Environment Simulation and Pollution Control

169

Chinese Academy of Sciences

147

University of Chinese Academy of Sciences

Zhejiang University

Leibniz Institute for Tropospheric Research

Nanjing University of Information Science and Technology

University of Helsinki

Fudan University

Tsinghua University

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In suit constructing S-scheme FeOOH/MgIn2S4 heterojunction with boosted interfacial charge separation and redox activity for efficiently eliminating antibiotic pollutant

Chemosphere (2022)

Jin Luo Pingping Lin Pilang Zheng Xunfu Zhou Xiaomei Ning

Oxidizing agent

Visible spectrum

Nanorod

Degradation

Charge carrier

10.1016/j.chemosphere.2022.134297

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Citations (109)

Characterization of the volatile fraction of laboratory-generated aerosol particles by thermodenuder-aerosol mass spectrometer coupling experiments

Journal of Aerosol Science (2009)

Zhijun Wu Laurent Poulain Birgit Wehner Alfred Wiedensohler Hartmut Herrmann

Succinic acid

Ammonium sulfate

Mass fraction

Glutaric acid

Decarboxylation

Volatilisation

10.1016/j.jaerosci.2009.03.007

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Citations (23)

Simultaneously enhancing the thermal stability and electrochemical performance of solid polymer electrolytes by incorporating rod-like Zn2(OH)BO3 particles

International Journal of Hydrogen Energy (2020)

Zhijun Wu Zhengkun Xie Jing Wang Tao Yu Xiao Du

Thermal Stability

Electrochemical window

Fast ion conductor

10.1016/j.ijhydene.2020.05.086

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Citations (12)

Influence of Relative Humidity and Composition on PM_2.5 Phases in Northeast Asia

ACS Earth and Space Chemistry (2024)

Changjoon Seong Daeun Kim Rani Jeong Yanting Qiu Zhijun Wu

In Northeast Asia, the elevated levels of fine particulate matter (PM2.5) are an environmental concern, yet their physicochemical properties have been poorly characterized. Herein, we determined the phase states of PM2.5 in 92 filter samples collected from four different cities─Beijing, Seoul, Seosan, and Ulaanbaatar─during 2020–2022, within a temperature range of ∼290–293 K. We noted a distinct trend in the boundary relative humidity (RH) of liquid and semisolid phases within these PM2.5 samples. As the inorganic fraction increased, the RH of the liquid phase decreased, whereas that of the semisolid phase increased. This behavior was strongly influenced by the chemical composition of PM2.5. By incorporating ambient RH data from each city, we estimated the prevalent PM2.5 phase states within the planetary boundary layer of Northeast Asia. Our findings revealed that the dominant phase states of PM2.5 in these urban areas were liquid and semisolid. Additionally, we showed a critical threshold based on the aerosol liquid water content (ALWC) in PM2.5: a primarily liquid phase for ALWC/PM2.5 ratios of ≥∼0.5 and a predominantly semisolid phase for ALWC/PM2.5 ratios of <∼0.5. These insights could contribute to a better understanding of the mechanisms underlying aerosol pollution in Northeast Asia.

10.1021/acsearthspacechem.4c00019

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Citations (4)

Variation of particle number size distributions and chemical compositions at the urban and downwind regional sites in the Pearl River Delta during summertime pollution episodes

D. L. Yue Min Hu Zhijun Wu Song Guo Mingzhu Wen

Abstract. In order to characterize the features of particulate pollution in the Pearl River Delta (PRD) in the summer, continuous measurements of particle number size distributions and chemical compositions were simultaneously performed at Guangzhou urban site (GZ) and Back-garden downwind regional site (BG) in July 2006. Particle number concentration from 20 nm to 10 μm at BG was (1.7±0.8)×104 cm−3, about 40% lower than that at GZ, (2.9±1.1)×104 cm−3 with intensive traffic emissions. The total particle volume concentration at BG was 94±34 μm3 cm−3, similar to that at GZ, 96±43 μm3 cm−3. More 20–100 nm particles, significantly affected by the traffic emissions, were observed at GZ, while 100–660 nm particle number concentrations were similar at both sites as they are more regional. PM2.5 values were also similar at GZ (69±43 μg m−3) and BG (69±58 μg m−3), indicating the fine particulate pollution in the PRD region to be regional. Two kinds of pollution episodes, the accumulation pollution episode and the regional transport pollution episode, were observed. Fine particles over 100 nm dominated both number and volume concentrations of total particles during the late periods of these pollution episodes. Accumulation and secondary transformations are two main reasons for the nighttime accumulation pollution episode. SO4−2, NO3−, and NH4+ accounted for about 60% in 100–660 nm particle mass and PM2.5. When south or south-southeast wind prevailed in the PRD region, regional transport of pollutants takes place. Regional transport contributed about 30% to fine particulate pollution at BG during a regional transport case. Secondary transformation played an important role during regional transport, causing higher increase rates of secondary ions in PM1.0 than other species and shifting the peaks of sulfate and ammonium mass size distributions to larger sizes. SO4−2, NO3−, and NH4+ accounted for about 70% and 40% of PM1.0 and PM2.5, respectively.

Particle (ecology)

10.5194/acpd-10-14611-2010

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Citations (4)

Marine aerosol size distributions in the springtime over China adjacent seas

Atmospheric Environment (2007)

Peng Lin Min Hu Zhijun Wu Yuwen Niu Tong Zhu

Cloud condensation nuclei

China sea

10.1016/j.atmosenv.2007.04.045

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Citations (40)

Towards closing the gap between hygroscopic growth and CCN activation for secondary organic aerosols – Part 3: Influence of the chemical composition on the hygroscopic properties and volatile fractions of aerosols

Laurent Poulain Zhijun Wu Markus D. Petters Heike Wex E. Hallbauer

Abstract. The influence of varying levels of water mixing ratio, r, during the formation of secondary organic aerosol (SOA) from the ozonolysis of α-pinene on the SOA hygroscopicity and volatility was investigated. The reaction proceeded and aerosols were generated in a mixing chamber and the hygroscopic characteristics of the SOA were determined with LACIS (Leipzig Aerosol Cloud Interaction Simulator) and a Cloud Condensation Nuclei counter (CCNc). In parallel, a High-Resolution Time-of-Flight Aerodyne Aerosol Mass Spectrometer (HR-ToF-AMS) located downstream of a thermodenuder (TD) sampling from the mixing chamber, to collect mass spectra of particles from the volatile and non-volatile fractions of the SOA. Results showed that both hygroscopic growth and the volatile fraction of the SOA increased with increases in r inside the mixing chamber during SOA generation. An effective density of 1.40 g cm−3 was observed for the generated SOA when the reaction proceeded with r>1 g kg−1. Changes in the concentrations of the fragment CO2+ and the sum of CxHyOz+ (short name CHO) and CxHy+ (short name CH) fragments as measured by the HR-ToF-AMS were used to estimate changes in the oxidation level of the SOA with reaction conditions, using the ratios CO2+ to CH and CHO to CH. Under humid conditions, both ratios increased, corresponding to the presence of more oxygenated functional groups (i.e., carboxylic groups). This result is consistent with the α-pinene ozonolysis mechanisms which suggest that water interacts with the stabilized Criegee intermediate. The volatility and the hygroscopicity results show that SOA generation via ozonolysis of α-pinene in the presence of water vapour (r<16.884 g kg−1) leads to the formation of more highly oxygenated compounds that are more hygroscopic and more volatile than compounds formed under dry conditions.

Mixing ratio

Cloud condensation nuclei

Mass fraction

10.5194/acpd-9-16683-2009

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Citations (3)

Influence of cloud processing on CCN activation behaviour in the Thuringian Forest, Germany during HCCT-2010

Atmospheric chemistry and physics (2014)

Silvia Henning K. Dieckmann K. Ignatius Michael Schäfer Philipp Zedler

Abstract. Within the framework of the "Hill Cap Cloud Thuringia 2010" (HCCT-2010) international cloud experiment, the influence of cloud processing on the activation properties of ambient aerosol particles was investigated. Particles were probed upwind and downwind of an orographic cap cloud on Mt Schmücke, which is part of a large mountain ridge in Thuringia, Germany. The activation properties of the particles were investigated by means of size-segregated cloud condensation nuclei (CCN) measurements at 3 to 4 different supersaturations. The observed CCN spectra together with the total particle spectra were used to calculate the hygroscopicity parameter κ for the upwind and downwind stations. The upwind and downwind critical diameters and κ values were then compared for defined cloud events (FCE) and non-cloud events (NCE). Cloud processing was found to increase the hygroscopicity of the aerosol particles significantly, with an average increase in κ of 50%. Mass spectrometry analysis and isotopic analysis of the particles suggest that the observed increase in the hygroscopicity of the cloud-processed particles is due to an enrichment of sulfate and possibly also nitrate in the particle phase.

Cloud condensation nuclei

Orographic lift

Particle (ecology)

10.5194/acp-14-7859-2014

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Citations (33)

The variability in the relationship between black carbon and carbon monoxide over the eastern coast of China: BC aging during transport

Atmospheric chemistry and physics (2017)

Qingfeng Guo Min Hu Song Guo Zhijun Wu Jianfei Peng

Abstract. East Asia is a densely populated region with a myriad of primary emissions of pollutants such as black carbon (BC) and carbon monoxide (CO). To characterize primary emissions over the eastern coast of China, a series of field campaigns were conducted in 2011, including measurements from a ship cruise, island, and coastal receptor sites. The relationship between BC and CO is presented here for the first ship cruise (C1), the second ship cruise (C2), an island site (Changdao Island, CD), and a coastal site (Wenling, WL). The average BC mass concentrations were 2.43, 2.73, 1.09, 0.94, and 0.77 µg m−3 for CD, WL, C1-YS (Yellow Sea), C1-ES (East China Sea), and C2-ES, respectively. For those locations, the average CO mixing ratios were 0.55, 0.48, 0.31, 0.36, and 0.27 ppm. The high loadings of both BC and CO imply severe anthropogenic pollution over the eastern coast of China. Additionally, the linear correlation between BC and CO was regressed for each location. The slopes, i.e., the ratios of ΔBC to ΔCO derived from their relationship, correlated well with the ratios of diesel consumption to gasoline consumption in each province/city, which reveals vehicular emission to be the common source for BC and CO and that there are distinct fuel structures between North and South China. The ΔBC/ΔCO values at coastal sites (Changdao Island and Wenling) were much higher than those over the Yellow Sea and East China Sea, and the correlation coefficients also showed a decreasing trend from the coast to the sea. Therefore, the quantity of ΔBC/ΔCO and the correlation coefficients are possible indicators for the aging and removal of BC.

East coast

China sea

10.5194/acp-17-10395-2017

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Citations (20)

Traffic restrictions in Beijing during the Sino-African Summit 2006: aerosol size distribution and visibility compared to long-term in situ observations

Yafang Cheng Jost Heintzenberg Birgit Wehner Zhijun Wu Min Hu

Abstract. Based on the long-term in-situ observations of aerosol particle number size distributions and meteorological parameters, the traffic restriction measures during the Sino-African Summit (4–6 November 2006) in Beijing, China have been found to be remarkably efficient in reducing the number concentration of aerosol particles, in particular Aitken and accumulation mode particles, and in improving the visibility. The influence of traffic restriction in Beijing on the particle concentrations differed for different particle sizes. More significant effects on fine particles with diameters ranging from 40 to 800 nm have been found. Based on statistical analysis of long-term observation, under comparable weather conditions, the source strength of the particles in Aitken and accumulation modes seemingly was reduced by 40–60% when the traffic restrictions were in place. It may be mainly due to the reduction of secondary particle formation. Our size-dependent aerosol data also indicate that measures led to reductions in particulate air pollution in the optically most important diameter range, whereas further vehicle control measures may lead to an increase in ultrafine particle formation from the gas phase if the condensational sink further decreased. Assuming that there were no traffic restrictions and with normal levels of the vehicle emissions, the visibilities during the Summit would have been lower by about 50%. The importance of the restrictions is highest when the wind speed is lower than 3 m s−1. The fact that over 95% cases with visual range lower than 5 km during 2004 to 2007 occurred when the local wind speed was lower than 3 m s−1 may suggest that future traffic restrictions will lead to significant improvements of visibility in Beijing.

Ultrafine particle

Visibility

Summit

Particle (ecology)

10.5194/acpd-8-12971-2008

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Citations (4)