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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

Surrogate atmospheric dust particles generated from dune soils in laboratory: Comparison with field measurement

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Particuology 2023年第1期72卷 29-36页

作者： Feng Wu Na Song Tafeng Hu Steven Sai Hang Ho junji cao Daizhou Zhang State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi’an710061China Key Laboratory of Aerosol Chemistry and Physics Institute of Earth EnvironmentChinese Academy of SciencesXi’an710061China CAS Center for Excellence in Quaternary Science and Global Change Xi’an710061China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing100029China Faculty of Environmental and Symbiotic Sciences Prefectural University of KumamotoKumamoto 862-8502Japan Division of Atmospheric Sciences Desert Research InstituteRenoNV 89512United States

Desert dust strongly influences the climate and the environment by altering the radiation budget, participating in atmospheric chemical reactions, and engaging the biogeochemical cycle. Studying its impacts requires knowledge of the physical and chemical properties of the original particles from the source origin. Unfortunately, the field collection of atmospheric samples in the desert is impractical. Fine surface soil is thus considered an alternative material from which to obtain the information applicable to dust particles from the desert soil. In this study, a laboratory system was set up to generate dust particles with simulated natural wind erosion processes from surface soils or directly from desert surfaces. Surface soils and field dust were simultaneously collected during a local blowing dust event. The comparison between the laboratory-generated dust and the field dust showed a consistent trend in particle size distribution and chemical composition. The chemical compositions were found to have explainable differences with the Certified Reference Materials for Asian dust (CJ-2). The laboratory-generated dust particles with the system could be applied as surrogates for soil-emitted dust in desert areas.

关键词： Laboratory dust simulation system Asian dust Source profiles Particle sizes Chemical compositions

Preface to the Special Issue on Carbon Neutrality: Important Roles of Renewable Energies, Carbon Sinks, NETs, and non-CO_(2) GHGs

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Advances in Atmospheric Sciences 2022年第8期39卷 1207-1208页

作者： junji cao Ning ZENG Yi LIU Bengang LI Pengfei HAN Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China Department of Atmospheric and Oceanic Science and Earth System Science Interdisciplinary CenterUniversity of MarylandCollege Park 20742MarylandUSA State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Carbon Neutrality Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing100029China Sino-French Institute for Earth System Science Laboratory for Earth Surface ProcessesCollege of Urban and Environmental SciencesPeking UniversityBeijing 100871China

The year 2020 witnessed milestone commitments to carbon neutrality with the EU,China,USA,Japan,South Korea,Canada,and South Africa,each pledging to reach net-zero carbon *** that have adopted or have considered net-zero targets now represent 63%of the total contributions to global greenhouse gas(GHG)*** the efforts of all parties,the 26th Conference of the Parties(COP26)achieved a package of outcomes in the Glasgow Climate ***,a breakthrough consensus was reached on reducing coal,controlling methane,and halting deforestation(Wang et al.,2022,Page 1209).To achieve net-zero carbon,we need to take action to implement the Paris Agreement and the Glasgow Climate Pact Since the global temperature slowdown of the nationally determined contributions(NDC)scenario is only 0.6°C,all countries need to pursue stricter carbon reduction policies for a more sustainable world.(Fu et al,2022,Page 1209).

关键词： breakthrough neutral methane

Aerosol composition,sources,and secondary processing during autumn at a regional site in the Beijing-Tianjin-Hebei region

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Particuology 2023年第4期75卷 177-184页

作者： Yichen Wang Qiyuan Wang Jie Tian Yong Zhang Yunfei Wu Weikang Ran Renjian Zhang junji cao School of Public Policy and Administration Northwestern Polytechnical UniversityXi'an710129China Key Laboratory of Aerosol Chemistry and Physics State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an710061China CAS Center for Excellence in Quaternary Science and Global Change Xi'an710061China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing100029China Xianghe Observatoryof Whole Atmosphere Institute of Atmospheric PhysicsChinese Academy of SciencesXianghe CountyHebei Province065400China

Air pollution is serious during autumn in the Beijing-Tianjin-Hebei(BTH)region,but there are few studies that have utilized real-time observations and source apportionment of the autumn submicron aerosols in this *** this study,a quadrupole aerosol chemical speciation monitor(Q-ACSM)was deployed for the real-time measurement of the non-refractory compositions of submicron aerosols(NR-PM1)at a regional site(Xianghe)from October 3 to November 14,*** results showed that nitrate was the largest inorganic aerosol,and the oxygenated organic aerosol(OOA)was the largest organic aerosol in ***-like OA(HOA)was the largest organic aerosol When the NR-PM1 mass concentrations increased from the lowest to the highest bins,nitrate and biomass burning OA(BBOA)showed increasing trends in the suburban *** nitrate formation during the pollution epi-sodes resulted from both photochemical and aqueous *** reduce the particulate matter(PM2.5)concentrations and eliminate heavy pollution episodes,control measures should focus on reducing NO_(x),NH_(3),and volatile organic compound(VOCs)emissions.

关键词： Autumn Beijing-Tianjin-Hebei region Submicron aerosol Organic sources Control measures

The Chinese Carbon-Neutral Goal:Challenges and Prospects

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Advances in Atmospheric Sciences 2022年第8期39卷 1229-1238,I0027-I0030页

作者： Ning ZENG Kejun JIANG Pengfei HAN Zeke HAUSFATHER junji cao Daniel KIRK-DAVIDOFF Shaukat ALI Sheng ZHOU Department of Atmospheric and Oceanic Science and Earth System Science Interdisciplinary CenterUniversity of MarylandCollege Park 20742MarylandUSA State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Energy Research Institute National Development and Reform CommissionBeijing 100045China Carbon Neutrality Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Breakthrough Institute Oakland 94612CaliforniaUSA Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China Global Change Impact Study Centre Ministry of Climate ChangeIslamabad 45250Pakistan Institute of Energy Environment and EconomyTsinghua UniversityBeijing 100084China

On 22 September 2020,within the backdrop of the COVID-19 global pandemic,China announced its climate goal for peak carbon emissions before 2030 and to reach carbon neutrality before *** carbon-neutral goal is generally considered to cover all anthropogenic greenhouse *** planning effort is now in full swing in China,but the pathway to decarbonization is *** needed transition towards non-fossil fuel energy and its impact on China and the world may be more profound than its reform and development over the past 40 years,but the challenges are *** of four representative scenarios shows significant differences in achieving the carbon-neutral goal,particularly the contribution of non-fossil fuel energy *** high target values for nuclear,wind,and bioenergy have approached their corresponding resource limitations,with solar energy being the exception,suggesting solar’s critical *** also found that the near-term policies that allow for a gradual transition,followed by more drastic changes after 2030,can eventually reach the carbon-neutral goal and lead to less of a reduction in cumulative emissions,thus inconsistent with the IPCC 1.5°C *** challenges and prospects are discussed in the historical context of China’s socio-economic reform,globalization,international collaboration,and development.

关键词： carbon neutral carbon dioxide reductions energy system transformation distributed energy system model projections

High impact of vehicle and solvent emission on the ambient volatile organic compounds in a major city of northwest China

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Chinese Chemical Letters 2022年第5期33卷 2753-2756页

作者： Yonggang Xue Liqin Wang Suixin Liu Yu Huang Long Chen Long Cui Yan Cheng junji cao State Key Lab of Loess and Quaternary Geology(SKLLQG) Institute of Earth EnvironmentChinese Academy of Sciences(CAS)Xi’an 710061China CAS Center for Excellence in Quaternary Science and Global Change Xi’an 710061China Guanzhong Plain Ecological Environment Change and Comprehensive Treatment National Observation and Research Station Xi’an 710061China School of Human Settlements and Civil Engineering Xi’an Jiaotong UniversityXi’an 710049China

Monitoring of ambient volatile organic compounds(VOCs)was conducted within typical residentialcommercial area in the city of Xi’an in northwest China during typical ozone(O_(3))episodes,to investigate the major contributors to the characteristic of ambient VOCs and their impact on O_(3) *** the residential-commercial area,diurnal variation of VOCs was highly impacted by vehicle exhaust,fuel evaporation,and local solvent *** higher contributions(up to 60%)of VOCs from solvent use to the ozone formation potential were *** present findings highlight the urgent need for restrictions on the emission of VOCs from solvent use and non-vehicle-traffic-related sources,such as oil storage.

关键词： VOCs Vehicle exhaust Fuel evaporation Solvent using Northwest China

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