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| 1 | Black carbon aerosols and their radiative properties in the Pearl River Delta region显示文摘The climatic and environmental effects of atmospheric aerosols are a hot topic in global science community, and radiative properties of the aerosols are one of the important parameters in assessing climatic change. Here we studied the black carbon concentration and absorption coefficient measured with aethalometers, scattering coefficient measured with nephelometers, and single scattering albedo derived at an atmospheric composition watch station in Guangzhou from 2004 to 2007. Our main results are as follows. The data of black carbon concentration and absorption coefficients measured with instruments cannot be directly used until they are measured in parallel with internationally accepted instruments for comparison, calibration, and reduction. After evaluation of the data, the result shows that the monthly mean of BC concentration varies 3.1―14.8 μg·m-3 and the concentration decreases by about 1 μg·m-3 in average over the four years; It is higher in the dry season with a multi-year mean of 8.9 μg/m3 and lower in the rainy season with a multi-year mean of 8.0 μg·m-3; The extreme maximum of monthly mean concentration occurred in December 2004 and extreme minimum in July 2007, and a 4-year mean is 8.4 μg·m-3. It is also shown that monthly mean scattering coefficient derived varies 129 -565 Mm-1, monthly mean absorption coefficient 32-139 Mm-1, and monthly mean single scattering albedo 0.71-0.91, with annual mean values of 0.80, 0.82, 0.79 and 0.84 for 2004, 2005, 2006 and 2007, respectively. Three instruments were used to take simultaneous measurements of BC in PM10, PM2.5, and PM1 and the results showed that PM2.5 took up about 90% of PM10 and PM1 accounted for about 68% of PM2.5, and BC aerosols are mainly present in fine particulates. The variability of BC concentrations is quite consistent between the Nancun station (141 m above sea level) and the Panyu station (13 m above sea level), which are 8 km apart from each other. The concentration in higher altitude station (Panyu) is consistently lower than the lower altitude station (Nancun), and the difference of annual mean is about 4 μg·m-3. | WU Dui MAO JieTai DENG XueJiao TIE XueXi ZHANG YuanHang ZENG LiMin LI Fei TAN HaoBo BI XueYan HUANG XiaoYing CHEN Jing DENG Tao | 2009 | Science China Earth Sciences2009，52，8： | 58 |
| 2 | Fast increasing of surface ozone concentrations in Pearl River Delta characterized by a regional air quality monitoring network during 2006–2011显示文摘Based on the observation by a Regional Air Quality Monitoring Network including 16 monitoring stations, temporal and spatial variations of ozone(O3), NO2and total oxidant(Ox) were analyzed by both linear regression and cluster analysis. A fast increase of regional O3concentrations of 0.86 ppbV/yr was found for the annual averaged values from 2006 to 2011 in Guangdong, China. Such fast O3increase is accompanied by a correspondingly fast NOx reduction as indicated by a fast NO2 reduction rate of 0.61 ppbV/yr. Based on a cluster analysis, the monitoring stations were classified into two major categories – rural stations(non-urban) and suburban/urban stations. The O3concentrations at rural stations were relatively conserved while those at suburban/urban stations showed a fast increase rate of 2.0 ppbV/yr accompanied by a NO2 reduction rate of 1.2 ppbV/yr. Moreover, a rapid increase of the averaged O3 concentrations in springtime(13%/yr referred to 2006 level) was observed, which may result from the increase of solar duration, reduction of precipitation in Guangdong and transport from Eastern Central China. Application of smog production algorithm showed that the photochemical O3production is mainly volatile organic compounds(VOC)-controlled. However, the photochemical O3production is sensitive to both NOx and VOC for O3pollution episode. Accordingly, it is expected that a combined NOx and VOC reduction will be helpful for the reduction of the O3 pollution episodes in Pearl River Delta while stringent VOC emission control is in general required for the regional O3 pollution control. | Jinfeng Li Keding Lu Wei Lv Jun Li Liuju Zhong Yubo Ou Duohong Chen Xin Huang Yuanhang Zhang | 2014 | Journal of Environmental Sciences2014，26，1： | 51 |
| 3 | Contrasting trends of PM2.5 and surface-ozone concentrations in China from 2013 to 2017显示文摘Although much attention has been paid to investigating and controlling air pollution in China,the trends of air-pollutant concentrations on a national scale have remained unclear.Here,we quantitatively investigated the variation of air pollutants in China using long-term comprehensive data sets from 2013 to 2017,during which Chinese government made major efforts to reduce anthropogenic emission in polluted regions.Our results show a significant decreasing trend in the PM2.5 concentration in heavily polluted regions of eastern China,with an annual decrease of〜7%compared with measurements in 2013.The measured decreased concentrations of SO2>NO2 and CO(a proxy for anthropogenic volatile organic compounds)could explain a large fraction of the decreased PM2.5 concentrations in different regions.As a consequence;the heavily polluted days decreased significantly in corresponding regions.Concentrations of organic aerosol;nitrate;sulfate,ammonium and chloride measured in urban Beijing revealed a remarkable reduction from 2013 to 2017;connecting the decreases in aerosol precursors with corresponding chemical components closely.However;surface-ozone concentrations showed increasing trends in most urban stations from 2013 to 2017;which indicates stronger photochemical pollution.The boundary-layer height in capital c让ies of eastern China showed no significant trends over the Beijing-Tianjin-Hebei,Yangtze River Delta and Pearl River Delta regions from 2013 to 2017;which confirmed the reduction in anthropogenic emissions.Our results demonstrated that the Chinese government was successful in the reduction of particulate matter in urban areas from 2013 to 2017,although the ozone concentration has increased significantly;suggesting a more complex mechanism of improving Chinese air quality in the future. | Yonghong Wang Wenkang Gao Shuai Wang Tao Song Zhengyu Gong Dongsheng Ji Lili Wang Zirui Liu Guiqian Tang Yanfeng Huo Shili Tian Jiayun Li Mingge Li Yuan Yang Biwu Chu Tuukka Petaja Veli-Matti Kerminen Hong He Jiming Hao Markku Kulmala Yuesi Wang Yuanhang Zhang | 2020 | National Science Review2020，7，8： | 51 |
| 4 | Ozone source attribution during a severe photochemical smog episode in Beijing,China显示文摘Beijing,the capital of China,frequently suffers from the high levels of ozone in summer.A 3-D regional chemical transport model,the Comprehensive Air Quality Model with extensions(CAMx),has been used to simulate a heavy O3 pollution episode in Beijing during June 26―July 2,2000.Ozone Source Apportionment Technology(OSAT) and Geographic Ozone Assessment Technology(GOAT) were applied to quantify the contributions of the precursor emissions from different regions to O3 concentrations in Beijing,to identify the relative importance of different ways by which regional sources affected the O3 levels in Beijing urban areas,and to investigate the sensitivity of O3 formation to the precursors during the episode.The O3 pollution in Beijing showed a significant spatial distribution with strong regional contribution.The results suggested that the plume originating from Beijing urban areas greatly affected the O3 concentrations at the Dingling site,accounting for 55% of elevated O3 there,while O3 pollution in the Beijing urban areas resulted from both local emissions and those from Tianjin and the south of Hebei Province.Transport of O3 was responsible for about 70% of the regional O3 contribution to Beijing urban areas,while transport of O3 precursors accounted for the remainder.The formation of O3 was limited by volatile organic compounds(VOCs) in the urban areas of Beijing,while being more sensitive to NOx levels in the suburban and more remote areas.Therefore,it is necessary to consider a large number of factors,including impacts of emissions from different regions,the two modes of regional contribution as well as the sensitivity of O3 formation to precursors,in the design of emissions control strategies for O3 reduction in Beijing. | WANG XueSong LI JinLong ZHANG YuanHang XIE ShaoDong TANG XiaoYan | 2009 | Science China Chemistry2009，52，8： | 32 |
| 5 | Source apportionment and secondary organic aerosol estimation of PM_(2.5) in an urban atmosphere in China显示文摘PM2.5 is the key pollutant in atmospheric pollution in China.With new national air quality standards taking effect,PM2.5 has become a major issue for future pollution control.To effectively prevent and control PM2.5,its emission sources must be precisely and thoroughly understood.However,there are few publications reporting comprehensive and systematic results of PM2.5 source apportionment in the country.Based on PM2.5 sampling during 2009 in Shenzhen and follow-up investigation,positive matrix factorization(PMF)analysis has been carried out to understand the major sources and their temporal and spatial variations.The results show that in urban Shenzhen(University Town site),annual mean PM2.5 concentration was 42.2μg m?3,with secondary sulfate,vehicular emission,biomass burning and secondary nitrate as major sources;these contributed30.0%,26.9%,9.8%and 9.3%to total PM2.5,respectively.Other sources included high chloride,heavy oil combustion,sea salt,dust and the metallurgical industry,with contributions between 2%–4%.Spatiotemporal variations of various sources show that vehicular emission was mainly a local source,whereas secondary sulfate and biomass burning were mostly regional.Secondary nitrate had both local and regional sources.Identification of secondary organic aerosol(SOA)has always been difficult in aerosol source apportionment.In this study,the PMF model and organic carbon/elemental carbon(OC/EC)ratio method were combined to estimate SOA in PM2.5.The results show that in urban Shenzhen,annual SOA mass concentration was 7.5μg m?3,accounting for 57%of total organic matter,with precursors emitted from vehicles as the major source.This work can serve as a case study for further in-depth research on PM2.5 pollution and source apportionment in China. | HUANG XiaoFeng YUN Hui GONG ZhaoHeng LI Xiang HE LingYan ZHANG YuanHang HU Min | 2014 | Science China Earth Sciences2014，57，6： | 28 |
| 6 | Explicit diagnosis of the local ozone production rate and the ozone-NOx-VOC sensitivities显示文摘In the troposphere, ozone is a harmful gas compound to both human health and vegetation. Ozone is produced from the reaction of NO_x(@NO + NO_2) and VOCs(volatile organic compounds) with light. Due to the highly nonlinear relationships between ozone and its precursors, proper ozone mitigation relies on the knowledge of chemical mechanisms. In this study, an observation-based method is used to simulate ozone formation and elucidate its controlling factors for a rural site on the North China Plain. The instantaneous ozone production rate is calculated utilizing a box model using the dataset obtained from the Wangdu campaign. First, the model was operated in a time-dependent mode to calculate the ozone production rate at each time stamp. The calculated ozone formation rate showed a diurnal average maximum value of 17 ppbv/h(1-h diurnal averaged). The contribution of individual peroxy radicals to ozone production was analyzed. In addition, the functional dependence of calculated P(O_3) reveals that ozone production was in a NO_x-limited regime during the campaign. Furthermore, the missing peroxy radical source will further extend NO_x-limited conditions to earlier in the day, making NO_xlimitation dominate more of a day than the current chemical model predicts. Finally, a multiple scenarios mode,also known as EKMA(empirical kinetic modeling approach), was used to simulate the response of P(O_3) to the imaginary change in precursor concentrations. We found that ozone production was in the NO_x-limited region. However, the use of NO_2 measured by the molybdenum converter and/or the absence of a peroxy radical source in the current chemical model could over-emphasize the VOC-limited effect on ozone production. | Zhaofeng Tan Keding Lu Huabin Dong Min Hu Xin Li Yuhan Liu Sihua Lu Min Shao Rong Su Haichao Wang Yusheng Wu Andreas Wahner Yuanhang Zhang | 2018 | Science Bulletin2018，63，16： | 25 |
| 7 | Exploring atmospheric free-radical chemistry in China:the self-cleansing capacity and the formation of secondary air pollution显示文摘Since 1971,it has been known that the atmospheric free radicals play a pivotal role in maintaining the oxidizing power of the troposphere.The existence of the oxidizing power is an important feature of the troposphere to remove primary air pollutants emitted from human beings as well as those from the biosphere.Nevertheless,serious secondary air-pollution incidents can take place due to fast oxidation of the primary pollutants.Elucidating the atmospheric free-radical chemistry is a demanding task in the field of atmospheric chemistry worldwide,which includes two kinds of work:first,the setup of reliable radical detection systems;second,integrated field studies that enable closure studies on the sources and sinks of targeted radicals such as OH and NO3.In this review,we try to review the Chinese efforts to explore the atmospheric free-radical chemistry in such chemical complex environments and the possible link of this fast gas-phase oxidation with the fast formation of secondary air pollution in the city-cluster areas in China. | Keding Lu Song Guo Zhaofeng Tan Haichao Wang Dongjie Shang Yuhan Liu Xin Li Zhijun Wu Min Hu Yuanhang Zhang | 2019 | National Science Review2019，6，3： | 26 |
| 8 | Exploration of the formation mechanism and source attribution of ambient ozone in Chongqing with an observation-based model显示文摘An intensive field campaign was conducted in Chongqing during the summer of 2015 to explore the formation mechanisms of ozone pollution. The sources of ozone, the local production rates, and the controlling factors, as well as key species of volatile organic compounds(VOCs), were quantified by integrating a local ozone budget analysis, calculations of the relative incremental reactivity, and an empirical kinetic model approach. It was found that the potential for rapid local ozone formation exists in Chongqing. During ozone pollution episodes, the ozone production rates were found to be high at the upwind station Nan Quan, the urban station Chao Zhan, and the downwind station Jin-Yun Shan. The average local ozone production rate was 30×10^(-9) V/V h^(-1) and the daily integration of the produced ozone was greater than 180×10^(-9) V/V. High ozone concentrations were associated with urban and downwind air masses. At most sites, the local ozone production was VOC-limited and the key species were aromatics and alkene, which originated mainly from vehicles and solvent usage. In addition, the air masses at the northwestern rural sites were NO_x-limited and the local ozone production rates were significantly higher during the pollution episodes due to the increased NOx concentrations. In summary, the ozone abatement strategies of Chongqing should be focused on the mitigation of VOCs. Nevertheless, a reduction in NO_x is also beneficial for reducing the regional ozone peak values in Chongqing and the surrounding areas. | SU Rong LU KeDing YU JiaYan TAN ZhaoFeng JIANG MeiQing LI Jing XIE ShaoDong WU YuSheng ZENG LiMin ZHAI ChongZhi ZHANG YuanHang | 2018 | Science China Earth Sciences2018，61，1： | 24 |
| 9 | Role of secondary aerosols in haze formation in summer in the Megacity Beijing显示文摘A field experiment from 18 August to 8 September 2006 in Beijing, China, was carried out. A hazy day was defined as visibility < 10 km and RH(relative humidity) < 90%. Four haze episodes, which accounted for ~ 60% of the time during the whole campaign, were characterized by increases of SNA(sulfate, nitrate, and ammonium) and SOA(secondary organic aerosol) concentrations. The average values with standard deviation of SO2-+4, NO-3, NH4 and SOA were 49.8(± 31.6), 31.4(±22.3), 25.8(±16.6) and 8.9(±4.1) μg/m3, respectively, during the haze episodes, which were 4.3, 3.4, 4.1, and 1.7 times those in the non-haze days. The SO2-4,NO-3, NH+4, and SOA accounted for 15.8%, 8.8%, 7.3%, and 6.0% of the total mass concentration of PM10 during the non-haze days. The respective contributions of SNA species to PM10 rose to about27.2%, 15.9%, and 13.9% during the haze days, while the contributions of SOA maintained the same level with a slight decrease to about 4.9%. The observed mass concentrations of SNA and SOA increased with the increase of PM10 mass concentration, however, the rate of increase of SNA was much faster than that of the SOA. The SOR(sulfur oxidation ratio) and NOR(nitrogen oxidation ratio) increased from non-haze days to hazy days, and increased with the increase of RH. High concentrations of aerosols and water vapor favored the conversion of SO2 to SO2-4and NO2 to NO-3, which accelerated the accumulation of the aerosols and resulted in the formation of haze in Beijing. | Tingting Han Xingang Liu Yuanhang Zhang Yu Qu Limin Zeng Min Hu Tong Zhu | 2015 | Journal of Environmental Sciences2015，27，5： | 22 |
| 10 | Trends in particulate matter and its chemical compositions in China from 2013–2017显示文摘Accurate determination of the atmospheric particulate matter mass concentration and chemical composition is helpful in exploring the causes and sources of atmospheric enthalpy pollution and in evaluating the rationality of environmental air quality control strategies.Based on the sampling and chemical composition data of PM2.5 in different key regions of China in the CARE-China observation network,this research analyzes the environmental air quality data released by the China National Environmental Monitoring Centre during the studied period to determine the changes in the particulate matter mass concentration in key regions and the evolution of the corresponding chemical compositions during the implementation of the Action Plan for Prevention and Control of Air Pollution from 2013-2017.The results show the following.(1)The particulate matter mass concentration in China showed a significant downward trend;however,the PM2.5 annual mass concentration in 64%of cities exceeds the New Chinese Ambient Air Quality Standard(CAAQS)GradeⅡ(GB3095-2012).The region to the east of the Taihang Mountains,the Fenhe and Weihe River Plain and the Urumqi-Changji regions in Xinjiang,all have PM2.5 concentration loading that is still high,and heavy haze pollution occurred frequently in the autumn and winter.(2)During the heavy pollution in the autumn and winter,the concentrations of sulfate and organic components decreased significantly.The mean SO42-concentration in PM2.5 decreased by 76%,12%,81%and 38%in Beijing-Tianjin-Hebei(BTH),the Pearl River Delta(PRD),the Sichuan-Chongqing region(SC)and the Fenhe and Weihe River Plain,respectively.The mean organic matter(OM)concentration decreased by 70%,44%,48%and 31%,respectively,and the mean concentration of NH4+decreased by 68%,1.6%,38%and 25%,respectively.The mean elemental carbon(EC)concentration decreased by 84%and 20%in BTH and SC,respectively,and it increased by 61%and 11%in the PRD and Fenhe and Weihe River Plain,respectively.The mean concentration of mineral and unresolved chemical components(MI)dropped by 70%,24%and 13%in BTH,the PRD and the Fenhe and Weihe River Plain,respectively.The change in the PM2.5 chemical composition is consistent with the decrease of the PM2.5mass concentration.(3)In 2015,the mean OM concentration contributions to fine particles and coarse particles were 13-46%and 46-57%,respectively,and the mean MI concentration contributions to fine particles and coarse and particles were 31-60%and 39-73%,respectively;these values are lower than the 2013 values from the key regions,which is the most important factor behind the decrease of the particulate matter mass concentration.From 2013 to 2015,among the chemical components of different particle size fractions,the peak value of the coarse particle size fraction decreased significantly,and the fine particle size fractions of SO42-,NO3-,and NH4+decreased with the decrease of the particulate matter mass concentration in different particle size fractions.The fine-particle size peaks of SO42-,NO3-and NH4+shifted from 0.65-1.1μm to the finer size range of0.43-0.65μm during the same time frame. | Yuesi WANG Wenjie LI Wenkang GAO Zirui LIU Shili TIAN Rongrong SHEN Dongsheng JI Shuai WANG Lili WANG Guiqian TANG Tao SONG Mengtian CHENG Gehui WANG Zhengyu GONG Jiming HAO Yuanhang ZHANG | 2019 | Science China Earth Sciences2019，62，12： | 23 |
| 11 | Evaluation and intercomparison of ozone simulations by Models-3/CMAQ and CAMx over the Pearl River Delta显示文摘Ozone pollution over the Pearl River Delta (PRD) in October 2004 has been simulated using the regional air quality models Models-3/CMAQ and CAMx. The results from both models were evaluated and compared with the observed concentrations from 12 monitoring stations. By integrated process rate analysis, the influences of different physical and chemical processes were quantified, and the causes of the deviations between the two models were investigated. Both CMAQ and CAMx repro- duced the magnitudes and variations of ozone at most stations over the PRD. The correlation coefficients (R) between the sim- ulated results and monitoring data were 0.73 for CMAQ and 0.74 for CAMx. The normalized mean bias (NMB) for CMAQ and CAMx over the 12 sites was ?8.5% and 8.8% on average, respectively. The normalized mean error (NME) for CMAQ and CAMx was 36.7% and 37.9%, respectively. The correlation between the results of two models was very high (R = 0.92), and their simulated ozone spatial distributions exhibited common features. But the values obtained using CMAQ simulation were about 17% lower than those obtained using CAMx on average. The results of simulations using the two models were not identical in certain regions, or for different types of monitoring stations. The differences in dry deposition, reaction parameters and vertical transport near the Pearl River Estuary can account for the discrepancies in the results obtained using the two models. In the upwind areas, the discrepancy in the boundary concentration of the finest nest was the main cause of the higher values obtained using CAMx compared with those obtained using CMAQ. There is a need for CAMx to provide more choices of dry deposition algo- rithms. Improvement of the calculation methods for photolysis rates would also improve the ozone simulation of CMAQ. | SHEN Jin WANG XueSong LI JinFeng LI YunPeng ZHANG YuanHang | 2011 | Science China Chemistry2011，54，11： | 20 |
| 12 | Chemical characterization of size-resolved aerosols in four seasons and hazy days in the megacity Beijing of China显示文摘Size-resolved aerosol samples were collected by MOUDI in four seasons in 2007 in Beijing. The PM10 and PM1.8mass concentrations were 166.0 ± 120.5 and 91.6 ± 69.7 μg/m^3, respectively,throughout the measurement, with seasonal variation: nearly two times higher in autumn than in summer and spring. Serious fine particle pollution occurred in winter with the PM1.8/PM10 ratio of 0.63, which was higher than other seasons. The size distribution of PM showed obvious seasonal and diurnal variation, with a smaller fine mode peak in spring and in the daytime. OM(organic matter = 1.6 × OC(organic carbon)) and SIA(secondary inorganic aerosol) were major components of fine particles, while OM, SIA and Ca_2+were major components in coarse particles. Moreover, secondary components, mainly SOA(secondary organic aerosol) and SIA,accounted for 46%–96% of each size bin in fine particles, which meant that secondary pollution existed all year. Sulfates and nitrates, primarily in the form of(NH_4)_2SO_4, NH_4NO_3, Ca SO_4, Na_2SO_4 and K_2SO_4, calculated by the model ISORROPIA II, were major components of the solid phase in fine particles. The PM concentration and size distribution were similar in the four seasons on non-haze days, while large differences occurred on haze days, which indicated seasonal variation of PM concentration and size distribution were dominated by haze days. The SIA concentrations and fractions of nearly all size bins were higher on haze days than on non-haze days, which was attributed to heterogeneous aqueous reactions on haze days in the four seasons. | Kang Sun Xingang Liu Jianwei Gu Yunpeng Li Yu Qu Junling An Jingli Wang Yuanhang Zhang Min Hu Fang Zhang | 2015 | Journal of Environmental Sciences2015，27，6： | 19 |
| 13 | Trends of Extreme Precipitation in Eastern China and Their Possible Causes显示文摘Significant increases of heavy precipitation and decreases of light precipitation have been reported over widespread regions of the globe. Global warming and effects of anthropogenic aerosols have both been proposed as possible causes of these changes. We examine data from urban and rural meteorological stations in eastern China(1955–2011) and compare them with Global Precipitation Climatology Project(GPCP) data(1979–2007) and reanalysis data in various latitude zones to study changes in precipitation extremes. Significant decreases in light precipitation and increases in heavy precipitation are found at both rural and urban stations, as well as low latitudes over the ocean, while total precipitation shows little change.Characteristics of these changes and changes in the equatorial zone and other latitudes suggest that global warming rather than aerosol effects is the primary cause of the changes. In eastern China, increases of annual total dry days(28 days) and 10 consecutive dry days(36%) are due to the decrease in light precipitation days, thereby establishing a causal link among global warming, changes in precipitation extremes, and higher meteorological risk of floods and droughts. Further, results derived from the GPCP data and reanalysis data suggest that the causal link exists over widespread regions of the globe. | LIU Run LIU Shaw Chen Ralph J.CICERONE SHIU Chein-Jung LI Jun WANG Jingli ZHANG Yuanhang | 2015 | Advances in Atmospheric Sciences2015，32，8： | 19 |
| 14 | Aerosol effects on ozone concentrations in Beijing:A model sensitivity study显示文摘Most previous O 3 simulations were based only on gaseous phase photochemistry.However,some aerosol-related processes,namely,heterogeneous reactions occurring on the aerosol surface and photolysis rate alternated by aerosol radiative influence,may affect O 3 photochemistry under high aerosol loads.A three-dimensional air quality model,Models-3/Community Multi-scale Air Quality-Model of Aerosol Dynamics,Reaction,Ionization,and Dissolution,was employed to simulate the effects of the above-mentioned processes on O 3 formation under typical high O 3 episodes in Beijing during summer.Five heterogeneous reactions,i.e.,NO 2,NO 3,N 2 O 5,HO 2,and O 3,were individually investigated to elucidate their effects on O 3 formation.The results showed that the heterogeneous reactions significantly affected O 3 formation in the urban plume.NO 2 heterogeneous reaction increased O 3 to 90 ppb,while HO 2 heterogeneous reaction decreased O 3 to 33 ppb.In addition,O 3 heterogeneous loss decreased O 3 to 31 ppb.The effects of NO 2,NO 3,and N 2 O 5 heterogeneous reactions showed opposite O 3 concentration changes between the urban and extra-urban areas because of the response of the reactions to the two types of O 3 formation regimes.When the aerosol radiative influence was included,the photolysis rate decreased and O 3 decreased significantly to 73 ppb O 3.The two aerosol-related processes should be considered in the study of O 3 formation because high aerosol concentration is a ubiquitous phenomenon that affects the urban-and regional air quality in China. | Jun Xu Yuanhang Zhang Shaoqing Zheng Youjiang He | 2012 | Journal of Environmental Sciences2012，24，4： | 15 |
| 15 | Progress of the key materials for organic solar cells显示文摘Organic solar cells have attracted academic and industrial interests due to the advantages like lightweight,flexibility and roll-to-roll fabrication.Nowadays,18%power conversion efficiency has been achieved in the state-of-the-art organic solar cells.The recent rapid progress in organic solar cells relies on the continuously emerging new materials and device fabrication technologies,and the deep understanding on film morphology,molecular packing and device physics.Donor and acceptor materials are the key materials for organic solar cells since they determine the device performance.The past 25 years have witnessed an odyssey in developing high-performance donors and acceptors.In this review,we focus on those star materials and milestone work,and introduce the molecular structure evolution of key materials.These key materials include homopolymer donors,D-A copolymer donors,A-D-A small molecular donors,fullerene acceptors and nonfullerene acceptors.At last,we outlook the challenges and very important directions in key materials development. | Yang Tong Zuo Xiao Xiaoyan Du Chuantian Zuo Yuelong Li Menglan Lv Yongbo Yuan Chenyi Yi Feng Hao Yong Hua Ting Lei Qianqian Lin Kuan Sun Dewei Zhao Chunhui Duan Xiangfeng Shao Wei Li Hin-Lap Yip Zhengguo Xiaol Bin Zhang Qingzhen Bian Yuanhang Cheng Shengjian Liu Ming Cheng Zhiwen Jin Shangfeng Yang Liming Ding | 2020 | Science China Chemistry2020，63，6： | 15 |
| 16 | Sources and characteristics of fine particles over the Yellow Sea and Bohai Sea using online single particle aerosol mass spectrometer显示文摘Marine aerosols over the East China Seas are heavily polluted by continental sources. During the Chinese Comprehensive Ocean Experiment in November 2012, size and mass spectra of individual atmospheric particles in the size range from 0.2 to 2.0 μm were measured on board by a single particle aerosol mass spectrometer(SPAMS). The average hourly particle number(PN)was around 4560 ± 3240 in the South Yellow Sea(SYS), 2900 ± 3970 in the North Yellow Sea(NYS), and 1700 ± 2220 in the Bohai Sea(BS). PN in NYS and BS varied greatly over 3 orders of magnitude, while that in SYS varied slightly. The size distributions were fitted with two log-normal modes. Accumulation mode dominated in NYS and BS, especially during episodic periods. Coarse mode particles played an important role in SYS. Particles were classified using an adaptive resonance theory based neural network algorithm(ART-2a). Six particle types were identified with secondary-containing, aged sea-salt, soot-like, biomass burning, fresh sea-salt,and lead-containing particles accounting for 32%, 21%, 18%, 16%, 4%, and 3% of total PN,respectively. Aerosols in BS were relatively enriched in particles from anthropogenic sources compared to SYS, probably due to emissions from more developed upwind regions and indicating stronger influence of continental outflow on marine environment. Variation of source types depended mainly on origins of transported air masses. This study examined rapid changes in PN, size distribution and source types of fine particles in marine atmospheres. It also demonstrated the effectiveness of high-time-resolution source apportionment by ART-2a. | Huaiyu Fu Mei Zheng Caiqing Yan Xiaoying Li Huiwang Gao Xiaohong Yao Zhigang Guo Yuanhang Zhang | 2015 | Journal of Environmental Sciences2015，27，3： | 12 |
| 17 | Characteristics and formation mechanism of regional haze episodes in the Pearl River Delta of China显示文摘To investigate the characteristics and the specific mechanism of continuous haze,comprehensive measurements were conducted from 15 October to 19 November in the Atmospheric Environment Monitoring Super-Station in Heshan of Guangdong province.Five haze episodes occurred in October and November 2014 in the Pearl River Delta(PRD)region. The meteorological parameters, gas data, chemical compositions, and optical parameters of the aerosols were obtained. Among these events, the second haze episode,with the highest concentration of PM2.5 of 187.51 μg/m^3, was the most severe. NO^3-was always higher than SO_4^(2-), which indicated that motor vehicles played an important role in the haze, even though the oxidation rate from SO_2 to SO_4^(2-)was faster than that of NOXto NO_3^-. The difference between the hourly averages of Na+and K+during the haze episode and clean days was small, implying that straw combustion and sea salt had no significant effect on the occurrence of haze, and the backward trajectories of the air masses also conformed with this result. The air pollutants were difficult to disperse because of the significant decrease in the planetary boundary layer(PBL) height. Relative humidity played a crucial role in the formation of haze by leading to hygroscopic growth of the diameter of aerosols. | Wenguang Li Xingang Liu Yuanhang Zhang Kang Sun Yusheng Wu Rui Xue Limin Zeng Yu Qu Junling An | 2018 | Journal of Environmental Sciences2018，30，1： | 11 |
| 18 | Chemical characteristics of size-resolved aerosols in winter in Beijing显示文摘Size-resolved aerosols were continuously collected by a Nano Sampler for 13 days at an urban site in Beijing during winter 2012 to measure the chemical composition of ambient aerosol particles. Data collected by the Nano Sampler and an ACSM(Aerodyne Aerosol Chemical Speciation Monitor) were compared. Between the data sets,similar trends and strong correlations were observed,demonstrating the validity of the Nano Sampler. PM10 and PM2.5concentrations during the measurement were 150.5 ± 96.0 μg/m3(mean ± standard variation)and 106.9 ± 71.6 μg/m3,respectively. The PM2.5/PM10 ratio was 0.70 ± 0.10,indicating that PM2.5dominated PM10. The aerosol size distributions showed that three size bins of 0.5–1,1–2.5 and 2.5–10 μm contributed 21.8%,23.3% and 26.0% to the total mass concentration(TMC),respectively. OM(organic matter) and SIA(secondary ionic aerosol,mainly SO42-,NO3-and NH4+) were major components of PM2.5. Secondary compounds(SIA and secondary organic carbon) accounted for half of TMC(about 49.8%) in PM2.5,and suggested that secondary aerosols significantly contributed to the serious particulate matter pollution observed in winter. Coal burning,biomass combustion,vehicle emissions and SIA were found to be the main sources of PM2.5. Mass concentrations of water-soluble ions and undetected materials,as well as their fractions in TMC,strikingly increased with deteriorating particle pollution conditions,while OM and EC(elemental carbon) exhibited different variations,with mass concentrations slightly increasing but fractions in TMC decreasing. | Kang Sun Yu Qu Qiong Wu Tingting Han Jianwei Gu Jingjing Zhao Yele Sun Qi Jiang Ziqi Gao Min Hu Yuanhang Zhang Keding Lu Stephan Nordmann Yafang Cheng Li Hou Hui Ge Masami Furuuchi Mitsuhiko Hata Xingang Liu | 2014 | Journal of Environmental Sciences2014，26，8： | 9 |
| 19 | Daytime HONO formation in the suburban area of the megacity Beijing, China显示文摘Nitrous acid(HONO),as a primary precursor of OH radicals,has been considered one of the most important nitrogencontaining species in the atmosphere.Up to 30%of primary OH radical production is attributed to the photolysis of HONO.However,the major HONO formation mechanisms are still under discussion.During the Campaigns of Air Quality Research in Beijing and Surrounding Region(CAREBeijing2006)campaign,comprehensive measurements were carried out in the megacity Beijing,where the chemical budget of HONO was fully constrained.The average diurnal HONO concentration varied from 0.33 to 1.2 ppbv.The net OH production rate from HONO,POH(HONO)net,was on average(from 05:00 to 19:00)7.1×106 molecule/(cm3 s),2.7 times higher than from O3 photolysis.This production rate demonstrates the important role of HONO in the atmospheric chemistry of megacity Beijing.An unknown HONO source(Punknown)with an average of 7.3×106molecule/(cm3 s)was derived from the budget analysis during daytime.Punknown provided four times more HONO than the reaction of NO with OH did.The diurnal variation of Punknown showed an apparent photo-enhanced feature with a maximum around 12:00,which was consistent with previous studies at forest and rural sites.Laboratory studies proposed new mechanisms to recruit NO2 and J(NO2)in order to explain a photo-enhancement of of Punknown.In this study,these mechanisms were validated against the observation-constraint Punknown.The reaction of exited NO2 accounted for only 6%of Punknown,and Punknown poorly correlated with[NO2](R=0.26)and J(NO2)[NO2](R=0.35).These results challenged the role of NO2 as a major precursor of the missing HONO source. | YANG Qiang SU Hang LI Xin CHENG YaFang LU KeDing CHENG Peng GU JianWei GUO Song HU Min ZENG LiMin ZHU Tong ZHANG YuanHang | 2014 | Science China Chemistry2014，57，7： | 8 |
| 20 | Major reactive species of ambient volatile organic compounds (VOCs) and their sources in Beijing显示文摘Volatile organic compounds (VOCs) are important precursors of atmospheric chemical processes. As a whole mixture, the ambient VOCs show very strong chemical reactivity. Based on OH radical loss rates in the air, the chemical reactivity of VOCs in Beijing was calculated. The results revealed that alkenes, accounting for only about 15% in the mixing ratio of VOCs, provide nearly 75% of the reactivity of ambient VOCs and the C4 to C5 alkenes were the major reactive species among the alkenes. The study of emission characteristics of various VOCs sources indicated that these alkenes are mainly from vehicle exhaust and gasoline evaporation. The reduction of alkene species in these two sources will be effective in photochemical pollution control in Beijing. | SHAO Min FU Linlin LIU Ying LU Sihua ZHANG Yuanhang TANG Xiaoyan | 2005 | Science China Earth Sciences2005，48，z2： | 7 |
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