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Carbonaceous particles in the atmosphere and precipitation of the Nam Co region, central Tibet

Journal of Environmental Sciences 2010年第11期22卷 1748-1756页

作者： Jing Ming Cunde Xiao junying sun Shichang Kang Paolo Bonasoni State Key Laboratory of Cryospheric Sciences Cold and Arid Region Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China National Climate Center China Meteorological Administration Beijing 100081 China Laboratory for Atmospheric Chemistry Centre for Atmosphere Watch & Services China Meteorological Administration Beijing 100081 China Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China Institute for Atmospheric Sciences and Climate CNR Bologna Italy

A continuous air and precipitation sampling for carbonaceous particles was conducted in a field observatory beside Nam Co, Central Tibetan Plateau during July of 2006 through January of 2007. Organic carbon （OC） was the dominant composition of the carbonaceous particles both in the atmosphere （1660 ng/m ^3 ） and precipitation （476 ng/g） in this area, while the average elemental carbon （BC） concentrations in the atmosphere and precipitation were only 82 ng/m 3 and 8 ng/g, respectively. Very high OC/BC ratio suggested local secondary organic carbon could be a dominant contribution to OC over the Nam Co region, while BC could be mainly originated from Southern Asia, as indicated by trajectory analysis and aerosol optical depth. Comparison between the BC concentrations measured in Lhasa, those at ＂Nepal Climate Observatory at Pyramid （NCO-P）＂ site on the southern slope of the Himalayas, and Nam Co suggested BC in the Nam Co region reflected a background with weak anthropogenic disturbances and the emissions from Lhasa might have little impact on the atmospheric environment here, while the pollutants from the Indo-Gangetic Basin of Southern Asia could be transported to the Nam Co region by both the summer monsoon and the westerly.

关键词： carbonaceous particle elemental carbon organic carbon Nam Co Tibetan Plateau

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Enhanced Performance of Osteoblasts by Silicon Incorporated Porous TiO_2 Coating

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Journal of Materials Science & Technology 2012年第2期28卷 109-117页

作者： Quanming Wang Hongjie Hu Yuqing Qiao Zhengxiang Zheng junying sun Orthopaedic Department The First Affiliated Hospital of Soochow University 188 Shizi Street Suzhou 215006 China State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

Silicon （Si） incorporated porous TiO2 coating （Si-TiO2） prepared on titanium （Ti） by micro-arc oxidation （MAO） technique was demonstrated to be cytocompatible in previous studies. In view of the potential clinical applications, a detailed in vitro study of the biological activity of Si-Ti02 coating, in terms of osteoblast （MC3T3-EI cells） morphology, proliferation, differentiation and mineralization was performed. Immunofluo- rescent staining indicated that cells seeded on the Si-TiO2 coating showed improved adhesion with developing mature cytoskeletons, which contained numerous distinct and well-defined actin stress fibers in the cell mem- branes compared with those on the Ti02 coating and Ti plate. Results from proliferation assay showed that the proliferation rate of cells seeded on the Si-TiO2coating was significantly faster than that on the TiO2 coating and Ti plate. Furthermore, the analysis of osteogenic gene expression demonstrated that the Si-Ti02 coating stimulated the expression of osteoblast-related genes and promoted differentiation and mineralization of MC3T3-EI cells. In addition, the Si-TiO2 coating differentially regulated Wnt signaling pathway by up-regulating the expression of low-density lipoprotein （LDL） receptor-related protein 5 （LrpS）, and downregulating the expression of Dickkopf-1 （Dkkl）. All together, these results indicate that the investigated titanium with Si-TiO2 coating is biocompatible and a good candidate material used as implants.

关键词： Micro-arc oxidation Silicon TiO2 Osteoblast Gene expression

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Biological Activity and Antibacterial Property of Nano-structured TiO_2 Coating Incorporated with Cu Prepared by Micro-arc Oxidation

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Journal of Materials Science & Technology 2013年第3期29卷 237-244页

作者： Wei Zhu Zhenxiang Zhang Beibei Gu junying sun Lixian Zhu Orthopedic Department The First Affiliated Hospital of Soochow University Orthopedic Department Orthopedic DepartmentThe Affiliated Taizhou People's Hospital of Nantong University

Micro-arc oxidized Cu-incorporated TiO2 coatings （Cu-TiO2） were prepared in the Ca, P, Cu-containing electrolyte to obtain an implant material with superior biological activity and antibacterial property. The surface topography, phase, and element composition of the TiO2 and Cu-TiO2 coatings were characterized by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and energy-dispersive X-ray spectrometry （EDS）, respectively. Staphylococcus aureus （S. aureus） was selected to evaluate the antibacterial property of the Cu-TiO2 coatings, whereas osteoblastic MG63 cells were cultured on the coatings to investigate the biological activity. The obtained results demonstrated that Cu element was successfully incorporated into the porous nano-structured TiO2 coatings, which did not alter apparently the surface topography and phase composition of the coatings as compared to the Cu-free TiO2 coatings. Moreover, the antibacterial studies suggested that the Cu-incorporated TiO2 coatings could significantly inhibit the adhesion of S. aureus. In addition, the in vitro biological evaluation displayed that the adhesion, proliferation and differentiation of MG63 cells on the Cu-incorporated coatings were enhanced as compared to those on the Cu-free coatings and Ti plates. In conclusion, the innovative Cu-incorporated nano-structured TiO2 coatings on Ti substrate with excellent antibacterial property and biological activity are promising candidates for orthopedic implant.

关键词： Micro-arc oxidation Copper Biological activity Antibacterial property

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Background concentrations of reactive gases and the impacts of long-range transport at the Jinsha regional atmospheric background station

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Science China Earth Sciences 2011年第10期54卷 1604-1613页

作者： LIN WeiLi XU XiaoBin sun junying LIUXiWen WANG Ying Key Laboratory for Atmospheric Chemistry Centre for Atmosphere Watch & Services Chinese Academy of Meteorological Sciences Beijing 100081 China Tibet Institute of Plateau Atmospheric and Environmental Science Lhasa 850000 China Wuhan Central Meteorological Observatory Wuhan 430074 China

Lorentz curve fittings are applied to frequency distributions of the concentrations of O3, CO, NOx and SO2 recorded at the Jinsha regional atmospheric background station （JSH） from June 2006 to July 2007, and the peak concentrations of these species for the different seasons are obtained. The peak concentrations are considered to be representative of different background levels for certain processes. The peak concentrations are compared with the corresponding mean （median） concentrations, and the suitability and limitations of the mean （median） values as the background levels are discussed. The mean （median） values might represent the background concentrations in the region under some circumstances, but in other cases these values often underestimate or overestimate the true background concentrations owing to the transport of pollutants and other factors. The effects of air masses transported from different regions on the pollutant background concentrations are obtained by analyzing the 72-hour backward trajectories of air masses 100m above the ground at JSH, These trajectories are estimated using the HYSPLIT model and then clustered for the measurement period. The spatial distribution and seasonal variations of trajectories and the corresponding mean concentrations of O3, SO〉 NOx and CO for different clusters are analyzed. After filtering the seasonal changes in pollutant concentrations, the relative influences of air masses from different regions are obtained. The results show that JSH can be used to obtain the atmospheric background information of different air masses originating from or passing over the Yangtze River Delta, Central South China and the Jianghan Plain. Air masses from Central China, South China, and the western Yangtze River Delta contribute significantly to O3 at JSH. Air masses from the north and northeast of JSH （i.e., the Jianghan Plain, Huang-Huai Plain and North China Plain） and the south （Central South China） contribute significantly to SO2

关键词： Jinsha regional atmosphere background station background signal Lorentz curve fitting air transport O3 CO NOx SO2

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Intensified wintertime secondary inorganic aerosol formation during heavy haze pollution episodes(HPEs) in Beijing,China

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Journal of Environmental Sciences 2022年第4期34卷 503-513页

作者： Lingyan Wu Xiaoye Zhang junying sun Yu Wang Junting Zhong Zhaoyang Meng State Key Laboratory of Severe Weather&Key Laboratory of Atmospheric Chemistry of CMA Chinese Academy of Meteorological SciencesBeijing 100081China

Air pollution in China is complex,and the formation mechanism of chemical components in particulate matter is still *** study selected three consecutive heavy haze pollution episodes(HPEs)during winter in Beijing for continuous field observation,including an episode with heavy air pollution under red *** days during the observation period were selected for *** HPE characteristics of Beijing in winter were:under the influence of adverse meteorological conditions such as high relative humidity,temperature inversion and low wind speed;and strengthening of secondary transformation reactions,which further intensified the accumulation of secondary aerosols and other pollutants,promoting the explosive growth of PM_(2.5).PM_(2.5)/CO values,as indicators of the contribution of secondary transformation in PM_(2.5),were approximately 2 times higher in the HPEs than the average PM_(2.5)/CO during the clean *** secondary inorganic aerosols(sulfate nitrate and ammonium salt)were significantly enhanced during the HPEs,and the conversion coefficients were remarkably *** addition,it is interesting to observe that the production of sulfate tended to exceed that of nitrate in the late stage of all three *** existence of aqueous phase reactions led to the explosive growth sulfur oxidation ratio(SOR)and rapid generation of sulfate under high relative humidity(RH>70%).

关键词： Water-soluble ions PM_(2.5) Heavy haze pollution episodes(HPEs) Sulfate Nitrate Secondary aerosol processes

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Key features of new particle formation events at background sites in China and their influence on cloud condensation nuclei

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Frontiers of Environmental Science & Engineering 2016年第5期10卷 107-117页

作者： Xiaojing SHEN junying sun Xiaoye ZHANG Yangmei ZHANG Lu ZHANG Ruxia FAN State Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of CMA Chinese Academy of Meteorological Sciences Beijing 100081 China State Key Laboratory of Cryospheric Sciences Cold and-Arid Region Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China College of Earth Science University of Chinese Academy of Sciences Beijing 100049 China

Long-term continuous measurements of particle number size distributions with mobility diameter sizes ranging from 3 to 800 nm were pertbrmed to study new particle formation （NPF） events at Shangdianzi （SDZ）, Mt. Tai （TS）, and Lin＇an （LAN） stations representing the background atmospheric conditions in the North China Plain （NCP） Central East China （CEC） and Yangtze River Delta （YRD） regions, respectively. The mean formation rate of 3-nm particles was 6.3, 3.7, and 5.8 cm -3 .s-1, and the mean particle growth rate was 3.6, 6.0, and 6.2 nm. h at SDZ, TS, and LAN, respectively. The NPF, event characteristics at the three sites indicate that there may be a stronger source of low volatile vapors and higher condensational sink of pre-existing particles in the YRD region. The formation rate of NPF events at these sites, as well as the condensation sink, is approximately 10 times higher than some results reported at rural/urban sites in western countries. However, the growth rates appear to be 1 2 times higher. Approximately 12%-17% of all NPF events with nucleated particles grow to a climate- relevant size （〉50 nm）. These kinds of NPF events were normally observed with higher growth rate than the other NPF cases. Generally, the cloud condensation nuclei （CCN） number concentration can be enhanced by approximately a factor of 2 6 on these event days. The mean value of the enhancement factor is lowest at LAN （2-3） and highest at SDZ （-4）. NPF events have also been found to have greater impact on CCN production in China at the regional scale than in the other background sites worldwide.

关键词： New particle formation Regional background Cloud condensation nuclei Growth rate Formation rate

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Chemical Components, Variation, and Source Identification of PM1 during the Heavy Air Pollution Episodes in Beijing in December 2016

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Journal of Meteorological Research 2018年第1期32卷 1-13页

作者： Yangmei ZHANG Yaqiang WANG Xiaoye ZHANG Xiaojing SHEN junying sun Lingyan WU Zhouxiang ZHANG Haochi CHE State Key Laboratory of Severe Weather/Key Laboratory of Atmospheric Chemistry of China Meteorological Administration Chinese Academy of Meteorological Sciences Beijing 100081 Center for Excellence in Regional Atmospheric Environment Institute of Urban Environment Chinese Academy of Sciences Xiamen 361021 College of Earth Science University of Chinese Academy of Sciences Beijing 100049

Air pollution is a current global concern. The heavy air pollution episodes（HPEs） in Beijing in December 2016 severely influenced visibility and public health. This study aims to survey the chemical compositions, sources, and formation processes of the HPEs. An aerodyne quadruple aerosol mass spectrometer（Q-AMS） was utilized to measure the non-refractory PM1（NR-PM1） mass concentration and size distributions of the main chemical components including organics, sulfate, nitrate, ammonium, and chloride in situ during 15–23 December 2016. The NR-PM1 mass concentration was found to increase from 6 to 188 μg m–3 within 5 days. During the most serious polluted episode, the PM1 mass concentration was about 2.6 times that during the first pollution stage and even 40 times that of the clean days. The formation rates of PM2.5 in the five pollution stages were 26, 22, 22, 32, and 67 μg m^（–3） h–1, respectively. Organics and nitrate occupied the largest proportion in the polluted episodes, whereas organics and sulfate dominated the submicron aerosol during the clean days. The size distribution of organics is always broader than those of other species, especially in the clean episodes. The peak sizes of the interested species grew gradually during different HPEs. Aqueous reaction might be important in forming sulfate and chloride, and nitrate was formed via oxidization and condensation processes. PMF（positive matrix factorization） analysis on AMS mass spectra was employed to separate the organics into different subtypes. Two types of secondary organic aerosol with different degrees of oxidation consisted of 43% of total organics. By contrast, primary organics from cooking, coal combustion, and traffic emissions comprised 57% of the organic aerosols during the HPEs.

关键词： heavy pollution PM1 chemical species sources evolution

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Robust prediction of hourly PM2.5 from meteorological data using LightGBM

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National Science Review 2021年第10期8卷 115-126页

作者： Junting Zhong Xiaoye Zhang Ke Gui Yaqiang Wang Huizheng Che Xiaojing Shen Lei Zhang Yangmei Zhang junying sun Wenjie Zhang State Key Laboratory of Severe Weather and Key Laboratory of Atmospheric Chemistry of China Meteorological Administration Chinese Academy of Meteorological Sciences School of Earth and Planetary Sciences University of Chinese Academy of Sciences Center for Excellence in Regional Atmospheric Environment Institute of Urban Environment Chinese Academy of Sciences

Retrieving historical fine particulate matter(PM2.5) data is key for evaluating the long-term impacts of PM2.5on the environment, human health and climate change. Satellite-based aerosol optical depth has been used to estimate PM2.5, but estimations have largely been undermined by massive missing values, low sampling frequency and weak predictive capability. Here, using a novel feature engineering approach to incorporate spatial effects from meteorological data, we developed a robust Light GBM model that predicts PM2.5at an unprecedented predictive capacity on hourly（R2= 0.75）, daily（R2= 0.84）, monthly（R2= 0.88） and annual（R2= 0.87） timescales. By taking advantage of spatial features, our model can also construct hourly gridded networks of PM2.5. This capability would be further enhanced if meteorological observations from regional stations were incorporated. Our results show that this model has great potential in reconstructing historical PM2.5datasets and real-time gridded networks at high spatial-temporal resolutions. The resulting datasets can be assimilated into models to produce long-term re-analysis that incorporates interactions between aerosols and physical processes.

关键词： PM2.5 spatial features hourly prediction high accuracy gridded networks

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Atmospheric Particle Hygroscopicity and the Influence by Oxidation State of Organic Aerosols in Urban Beijing

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Journal of Environmental Sciences 2023年第2期124卷 544-556页

作者： Sinan Zhang Xiaojing Shen junying sun Yangmei Zhang Xiaoye Zhang Can Xia Xinyao Hu Junting Zhong Jialing Wang Shuo Liu State Key Laboratory of Severe Weather&Key Laboratory of Atmospheric Chemistry of CMA Chinese Academy of Meteorological SciencesBeijing 100081China School of Atmospheric Physics Nanjing University of Information Science&TechnologyNanjing 210044China

A hygroscopic tandem differentialmobility analyser(H-TDMA)was used to observe the sizeresolved hygroscopic characteristics of submicron particles in January and April 2018 in urban *** probability distribution of the hygroscopic growth factor(HGF-PDF)in winter and spring usually showed a bimodal pattern,with more hygroscopic mode(MH)being more *** seasonal variation in particle hygroscopicity was related to the origin of air mass,which received polluted southerly air masses in spring and clean northwesterly air masses in *** showed stronger hygroscopic behaviour during heavy pollution episodes(HPEs)with elevated concentrations of secondary aerosols,especially higher mass fraction of nitrate,which were indicated using the PM2.5(particulate matter with diameter below 2.5μm)mass concentration normalised by CO mass *** hygroscopic parameter(κ)values were calculated using H-TDMA(κhtdma)and chemical composition(κchem).The closure study showed thatκchem was overestimated in winter afternoon when compared withκhtdma,because the organic particle hygroscopic parameter(κorg)was overestimated in the *** was influenced by the presence of a high concentration of hydrocarbon-like organic aerosol(HOA)with a weak water uptake ability.A positive relationship was observed betweenκorg and the ratio of oxygenated organic aerosol(OOA)and HOA,thereby indicating that the strong oxidation state enhanced the hygroscopicity of the *** study revealed the effect of local emission sources and secondary aerosol formation processes on particle hygroscopicity,which is of great significance for understanding the pollution formation mechanism in the North China Plain.

关键词： H-TDMA Hygroscopic parameter (κ) Organic aerosols Oxidation state Heavy pollution episode (HPE)

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Development of an integrating sphere calibration method for Cimel sunphotometers in China aerosol remote sensing network

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Particuology 2014年第2期12卷 88-99页

作者： Ran Tao Huizheng Che Quanliang Chen Yaqiang Wang junying sun Xiaochun Zhang Sai Lu Jianping Guo Hong Wang Xiaoye Zhang College of Atmospheric Sciences Chengdu University of Information Technology Key Laboratory of Atmospheric Chemistry(LAC) Chinese Academy of Meteorological Sciences(CAMS)CMA Meteorological Observation Center CMA

Based on the integrating sphere traced from the National Institute of Standards and Technology （NIST, USA）, a sphere calibration method and protocol for the China aerosol remote sensing network （CARSNET） Cimel sun photometer was established. Four CE318 sun photometers were verified using the proposed cal- ibration method and operational protocol. The calibration results showed that the instrument coefficients differed by less than 3% for visible （-5% for infrared） wavelengths from the original ones stated by Cimel Electronique. In situ validation experiment data showed that radiances at ±6° measured by sun collimator （aureole） were consistent with those measured by sky collimator （sky）, under both almucantar （ALMUC） and principal plane （PPLAN） scenarios. Differences at all wavelengths were less than 1%, indicating that the method and protocol are suitable for CARSNET field sun photometer calibration, and would benefit improvement of data quality and accuracy of network observations.

关键词： CE318 sunphotometer Integrating sphere CalibrationCARSNET

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