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Water-soluble organic matter with various polarities in PM_(2.5) over Xi'an,China:Abundance,functional groups,and light absorption

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Particuology 2024年第1期84卷 281-289页

作者： Xueting Yang Shasha Huang Dan Li Hongmei Xu Yaling Zeng Liu Yang Diwei Wang Ningning Zhang junji cao Zhenxing Shen Department of Environmental Science and Engineering Xi'an Jiaotong UniversityXi'an710049China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen518055China State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an710049China

Humic-like substances(HULIS)are a major component of brown carbon and consequently play a major role in climate *** this study,70 PM_(2.5) samples were collected from Xi'an in winter 2019 and summer *** HULIS(HULIS-n),acidic HULIS(HULIS-a),and high-polarity water-soluble organic compounds(HP-WSOC)were analyzed to determine their carbon concentrations and measure their ultraviolet-visible absorption and infrared *** the three components,HULIS-n had the highest carbon content in both winter(3.29±1.45μg m^(-3))and in summer(1.38±1.10μg m^(-3)).The semi-quantitative results for the functional groups revealed that HP-WSOC was rich in carboxylic acids and had high aromaticity in winter,whereas HULIS-n was rich in carboxylic acids in ***,HULJS-a was richer in nitrate esters and saturated aliphatic hydrocarbons in summer than in *** results for specific ultraviolet absorbance(SUVA)and E_(250)/E_(365) revealed that HULIS had higher molecular weight and aromaticity in winter than in ***-n dominated in the total light absorption of HULIS+HP-WSOC in both winter(73.08%)and summer(48.57%).Overall,the results on the carbon content,optical properties,and functional groups of WSOCs with differing polarity can improve un-derstanding of environmental and climatic effects.

关键词： Humic-like substances(HULIS) Aromaticity Fourier-transform infrared(FTIR) spectroscopy Light absorbance

Elaborations of the influencing factors on the formation of secondary inorganic aerosols in a heavily polluted urban area of China

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Journal of Environmental Sciences 2024年第4期138卷 406-417页

作者： Shuang Wang Qiyuan Wang Ting Zhang Suixin Liu Steven Sai Hang Ho Jie Tian Hui Su Yong Zhang Luyao Wang Tingting Wu junji cao School of Human Settlements and Civil Engineering Xi’an Jiaotong UniversityXi’an 710049China Key Laboratory of Aerosol Chemistry and Physics State Key Laboratory of Loess and Quaternary GeologyInstitute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China CAS Center for Excellence in Quaternary Science and Global Change Xi’an 710061China National Observation and Research Station of Regional Ecological Environment Change and Comprehensive Management in the Guanzhong Plain Xi’an 710061China Division of Atmospheric Sciences Desert Research InstituteRenoNevada89512United States Hong Kong Premium Services and Research Laboratory KowloonHong Kong SARChina Xi’an Institute for Innovative Earth Environment Research Xi’an 710061China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China

In this study,online water-soluble inorganic ions were detected to deduce the formation mechanism of secondary inorganic aerosol in Xianyang,China during *** dominant inorganic ions of sulfate(SO_(4)^(2-)),nitrate(NO_(3)^(-)),and ammonium(NH_(4)^(+))(the sum of those is abbreviated as SNA)accounted for 17%,21%,and 12% of PM_(2.5)mass,*** the air quality deteriorated from excellent to poor grades,the precursor gas sulfur dioxide(SO_(2))of SO_(4)^(2-)increased and then decreased with a fluctuation,while nitrogen dioxide(NO_(2))and ammonia(NH_(3)),precursors of NO_(3)^(-)and NH_(4)^(+),and SNA show increasing *** factors including boundary layer height(BLH),temperature,and wind speed also show decline trends,except relative humidity(RH).Meanwhile,the secondary conversion ratio shows a remarkable increasing trend,indicating that there was a strong secondary *** the perspective of chemical mechanisms,RH is positively correlated with sulfur oxidation ratios(SOR),nitrogen oxidation ratios(NOR),and ammonia conversion ratios,representing that the increase of humidity could promote the generation of ***,SOR and NOR were also positively related to the *** the one hand,the low wind speed and BLH led to the accumulation of *** the other hand,the increases of RH and ammonia promoted more formations of SNA and PM_(2.5).The results advance our identification of the contributors to the haze episodes and assist to establish more efficient emission controls in Xianyang,in addition to other cities with similar emission and geographical characteristics.

关键词： Haze episodes Secondary inorganic aerosol Secondary conversion ratio Meteorological factors

Growth of nitrate contribution to aerosol pollution during wintertime in Xi'an,northwest China:Formation mechanism and effects of NH_(3)

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Particuology 2024年第4期87卷 303-315页

作者： Hui Su Ting Zhang Suixin Liu Yao Qu Huan Li Jiamao Zhou Zhuzi Zhao Qiyuan Wang Lu Li Minxia Shen Shuoyuan Chen Steven Sai Hang Ho junji cao State Key Laboratory of Loess and Quaternary Geology.Key Laboratory ofAerosol Chemistry and Plhysics Institute of Earth EnvironmentChinese Acadery of SciencesXi'an 710061China Xi'an Institute for Innovative Earth Environment Research Xi'an 710061China National pbservation and Research Station of Regional Ecological Environment Change and Cornprehensive Management in the Guanzhong Plain Xi'an 710061China Shaanxi Key Laboratory of Atmospheric and Haze fog Pollution Prevention Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China University of Chinese Academy of Sciences Beijing 100049China School of Chemical and Environmental Engineering Jiangsu University of TechnologyChangzhou 213001China Division of Atmospheric Sciences Desert Research InstituteReno NV89512United States Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China

With the strengthened controls on SO2 emissions and extensive increases in motor vehicles'exhaust,aerosol pollution shifts from sulfate-rich to nitrate-rich in recent years in Xi'an,*** further gain insights into the factors on nitrate formation and efficiently mitigate air pollution,highly time-resolved observations of water-soluble inorganic ions(WSIIs)in PM_(2.5) were measured in a suburban area of Xi'an,China during *** concentration of total WSIIs is 39.8μg m-3 on average,accounting for 50.3%of PM_(2.5) *** contrast to a slight decrease in the mass fraction of SO_(4)^(2-),NO_(3)-shows a sig-nificant increase of the PM_(2.5) contribution with the aggravation of aerosol *** suggests the importance of NO_(3)-formation to haze ***,homogeneous reactions govern the formation of NO_(3)-,while alkali metals such as calcium and sodium play an additional role in retaining NO_(3)-in PM_(2.5) during clean ***,the heterogeneous hydrolysis reaction contributed more to NO_(3)-formation during the pollution periods under high relative *** investigation reveals that temperature,relative humidity,oxidant,and ammonia emissions facilitate rapid NO_(3)-*** the random forest(RF)model,NO_(3)-concentrations were successfully simulated with measured variables for the training and testing datasets(R2>0.95).Among these variables,CO,NH_(3),and NO_(2) were found to be the main factors affecting the NO_(3)-*** with the period without vehicle re-striction,the contributions of NO_(3)-and NH4+to PM_(2.5) mass decreased by 5.3%and 3.4%in traffic re-striction periods,*** vehicle restriction leads to the decreases of precursor gases of NO_(2),SO_(2),and NH_(3) by 12.8%,5.9%,and 27.6%,*** results demonstrate collaborative emission reduction of NO_(x) and NH_(3) by vehicle restrictions,and using new energy vehicles(or electric vehicles)can effectively alleviate particul

关键词： PM_(2.5) Water-soluble inorganic ions Nitrate formation Excess ammonium Vehicle restrictions

Aerosol pollution in China:Present and future impact on environment

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Particuology 2009年第6期7卷 426-431页

作者： Xuexi Tie junji cao National Center for Atmospheric Research Boulder CO USA SKLLQG Institute of Earth Environment Chinese Academy of Sdences No. 10 Fenghui South Road High-Tech Zone Xi'an 710075. China

With its dense population, rapid economic growth and dramatic rate of urbanization, China is experiencing extreme air pollution problems. This is particularly the case in Central-Eastern China （CEC）, where the two major cities of Beijing and Tianjin are located, in the Yangtze-River Delta （YRD） with the city of Shanghai, and in the Pearl-River Delta （PRD） with the mega-city of Gnangzhou. Space observations show that the atmospheric aerosol load in these three regions is considerably higher than, for example, in the urbanized regions of Europe and North America. The high aerosol concentrations in these regions have raised many environmental problems, such as impact on human health, visibility, and climate changes. In this paper, several crucial issues regarding aerosol pollution in these highly populated regions （CEC, YRD, and PRD） are discussed, including （1） when the aerosol load starts to rapidly increase in these regions; （2） how the high aerosol concentrations affects the environment; and （3） what the potential consequences are under possible low aerosol load in these regions. Discussion on these crucial issues might lead to some insight for better understanding of the characterizations of aerosol pollution due to the rapid economical development in China.

关键词： Aerosols Environment China Present and future effects

An analytical solution for the population balance equation using a moment method

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Particuology 2015年第1期13卷 194-200页

作者： Mingzhou Yu Jianzhong Lin junji cao Martin Seipenbusch Department of Physics China Jiliang University Institute of Earth Environment Chinese Academy of Sciences Institute for Mechanical Processes Engineering and Mechanics Karlsruhe Institute of Technology

Brownian coagulation is the most important inter-particle mechanism affecting the size distribution of aerosols. Analytical solutions to the governing population balance equation （PBE） remain a challenging issue. In this work, we develop an analytical model to solve the PBE under Brownian coagulation based on the Taylor-expansion method of moments. The proposed model has a clear advantage over conventional asymptotic models in both precision and efficiency. We first analyze the geometric standard deviation （GSD） of aerosol size distribution. The new model is then implemented to determine two analytic solu- tions, one with a varying GSD and the other with a constant GSD, The varying solution traces the evolution of the size distribution, whereas the constant case admits a decoupled solution for the zero and second moments, Both solutions are confirmed to have the same precision as the highly reliable numerical model, implemented by the fourth-order Runge-Kutta algorithm, and the analytic model requires significantly less computational time than the numerical approach. Our results suggest that the proposed model has great potential to replace the existing numerical model, and is thus recommended for the study of physical aerosol characteristics, especially for rapid predictions of haze formation and evolution,

关键词： Seif-preserving aerosols Analytical solution Taylor-expansion method of moments Population balance equation

Recent advances for aerosol and environment study in Asia

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Particuology 2013年第1期11卷 3-4页

作者： junji cao Judith C.Chow Key Lab of Aerosol Science & Technology Institute of Earth EnvironmentChinese Academy of Sciences Division of Atmospheric Sciences Desert Research InstituteRenoNVUSA

Rapid economic development over the past two decades in Asian countries such as China and India has raised awareness of pollution control measures necessary to protect public health and welfare. The 7th Asian Aerosol Conference （AAC） of the Asian Aerosol Research Assembly （AARA）, was held in Xi＇an, China, during August 17-20, 2011. The 7th AAC engaged 550 participants from the sciences, industry, and regulatory communities from 21 countries. The conference included -350 plenary, platform, and poster presentations. In this special issue of PARTICUOLOGY, 15 peer-reviewed scientific articles have been selected to publish from the conference abstracts to represent recent advances for aerosol and environment study in Asia.

关键词： Recent advances for aerosol and environment study in Asia PM

Great wall of solar panels to mitigate yellow dust storm

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Particuology 2014年第2期12卷 146-149页

作者： David Y.H.Pui junji cao Zhisheng An Jing Wang University of Minnesota Department of Mechanical EngineeringMinneapolisMN 55455USA Institute of Earth Environment Chinese Academy of Sciences ETH Zurich Institute of Environmental Engineering8093 ZurichSwitzerland EMPA Analytical Chemistry8600 Dubendorf Switzerland

Mitigation of the large scale yellow dust storm is a serious problem facing China. We propose the approach of building windbreak walls equipped with solar panels in the proximity of dust origins. The solar panels generate electricity in the sunny days; the walls break the wind and remove airborne dusts based on the impactor principle during wind storms. Preliminary calculation indicates the walls may be able to remove the major fraction of the airborne dusts and the generated electricity could be significant. More detailed studies are needed to prove the feasibility of the approach.

关键词： Solar panels Dust storm Mitigation Windbreak Sustainable development

2nd UMN-CAS Bilateral Seminar on PM2.5 science, health effects and control technologies, October 7-8, 2015 at 3M Innovation Center, Maplewood, MN, USA

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Particuology 2016年第4期14卷 141-142页

作者： David Y.H. Pui junji cao University of Minnesota MN 55455 USA Institute of Earth Environment Chinese Academy of Sciences Xi'an China

The First UMN-CAS Bilateral Seminar was successfully held in Xi＇an, China, May 27-28,2014. A summary of the 1 st Bilateral Seminar was published in Particuology 16 （2014）, 227-229. The Second UMN-CAS Bilateral Semi... 详细信息

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Elemental compositions of PM_(2.5) and TSP in Lijiang,southeastern edge of Tibetan Plateau during pre-monsoon period

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Particuology 2013年第1期11卷 63-69页

作者： Ningning Zhang junji cao Hongmei Xu Chongshu Zhu Key Laboratory of Aerosol Science & Technology SKLLQGInstitute of Earth EnvironmentChinese Academy of Sciences State Key Laboratory of Cryspheric Science Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences Institute of Global Environmental Change Xi'an Jiaotong University

PM2.5 and total suspended particulate （TSP） samples were collected at Lijiang, southeastern Tibetan Plateau, China. Sixteen elements （Al, Si, S, K, Ca, Cr, Mn, Ti, Fe, Ni, Zn, As, Br, Sb, Pb and Cu） were analyzed to investigate their elemental compositions during the pre-monsoon period. The results showed that Ca was the most abundant element in both PM2.5 and TSP samples. The enrichment factors （EFs） ofSi, Ti, Ca, Fe, K and Mn were all below 10 for both PM2.5 and TSP, and these elements also had lower PM2.5/TSP ratios （0.32-0.34）, suggesting that they were mainly derived from crustal sources. Elements Cu, Zn, S, Br and Sb showed strong enrichment in PM2.5 and TSP samples, with their PM2.5/TSP ratios ranging from 0.66 to 0.97, indicating that they were enriched in the fine fractions and influenced by anthropogenic sources. Analysis of the wind field at 500 hPa and calculations of back trajectories indicated that Al, Si, Ca, Ti, Cr, Mn and Fe can be influenced by transport from northwestern China during the dust-storm season, and that S, K, Ni, Br and Pb reached high concentrations during westerly transport from south Asia. Combined with the principle component analysis and correlation analysis, elements of PM2.5 samples were mainly from crustal sources, biomass burning emissions and regional traffic-related sources.

关键词： Elements Enrichment factors Pre-monsoon Lijiang