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Comparisons of two serious air pollution episodes in winter and summer in beijing

Journal of Environmental Sciences 2018年第7期30卷 141-154页

作者： Nianliang Cheng Yunting Li Bingfen Cheng Xin Wang Fan Meng Qin Wang Qihong Qiu key laboratory of airborne particulate matter monitoring technology of beijing Beijing Municipal Environmental Monitoring CenterBeijing 100048 China College of Water Sciences Beijing Normal University Beijing 100875 China Chinese Research Academy of Environmental Sciences Beijing 100012 China

Characteristics of two serious air pollution episodes（9–15 January, as the winter case; and30 June to 1 July, as the summer case）, which occurred in beijing in 2013 were investigated and compared using multi-method observations and numerical simulations. During these two air pollution episodes, PM2.5 concentrations varied significantly within beijing, with PM2.5 concentrations in southern parts of beijing being significantly higher than in northern areas. Typically, heavy air pollution episodes begin in the southern parts and disperse towards the northern parts of beijing. Clearly, synoptic patterns and the stability of atmospheric circulation patterns were the main factors controlling air pollution in *** the winter case, a warm center above 900 h Pa occurred over beijing. Meanwhile, in the summer case, although there was only a weak inversion, the convective inhibition energy was strong（over 200 J/k G）. This clearly influenced the duration of the air pollution event. Except for the local accumulation and secondary atmospheric reactions in both cases, regional straw burnings contributed a lot to the PM2.5 concentrations in summer *** the CAMxmodel, we established that regional transport contributed almost 59% to the PM2.5 averaged concentration in beijing in the winter case, but only 31% in the summer case. Thus, the winter case was a typical regional air pollution episode, while the summer case resulted from local accumulation straw burnings transportation and strong secondary atmospheric reactions. Given that air pollution is a regional problem in China, consistent and simultaneous implementation of regional prevention and control strategies is necessary to improve regional air quality.

关键词： Air pollution episodes PM2.5 Regional transport beijing Convective inhibition energy Straw burning

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Large scale air pollution prediction with deep convolutional networks

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Science China(Information Sciences) 2021年第9期64卷 116-126页

作者： Gao HUANG Chunjiang GE Tianyu XIONG Shiji SONG Le YANG Baoxian LIU Wenjun YIN Cheng WU Department of Automation Tsinghua University Department of Computer Science University of Toronto School of Environment Tsinghua University beijing key laboratory of airborne particulate matter monitoring technology Beijing Municipal Environmental Monitoring Center Insights Value technology CO. LTD.

Although considerable success has been achieved in urban air quality prediction(AQP) with machine learning techniques, accurate and long-term prediction is still challenging. One of the key issues for existing AQP approaches is that air quality monitoring stations are sparsely distributed, typically with around ten monitoring stations per city. As air quality may change abruptly in a local area, it is difficult to perform AQP accurately in areas that are far away from observation points. In addition, due to the large distance between every two monitoring stations, we cannot effectively leverage spatial relations among them to improve the AQP accuracy. In this paper, thanks to the development of low-cost air quality sensors, we are now able to collect a large-scale air quality dataset with 393 deployed air quality monitoring stations in a 120 km × 70 km region, which is more than ten times denser than existing AQP datasets. Further,we present a novel method to handle the data effectively. Specifically, we first convert the observed data from irregularly distributed monitoring stations into a regular image-like pollution map, which can then be processed with advanced deep convolutional networks. The experimental results show that the proposed approach can simultaneously model the temporal and spatial relations in our large-scale densely-observed dataset, leading to significantly improved AQP results.

关键词： air pollution prediction artificial intelligence convolutional neural network

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Understand the local and regional contributions on air pollution from the view of human health impacts

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Frontiers of Environmental Science & Engineering 2021年第5期15卷 133-143页

作者： Yueqi Jiang Jia Xing Shuxiao Wang Xing Chang Shuchang Liu Aijun Shi Baoxian Liu Shovan Kumar Sahu State key Joint laboratory of Environmental Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing100084China State Environmental Protection key laboratory of Sources and Control of Air Pollution Complex Beijing100084China beijing Municipal Research Institute of Environment Protection Beijing100037China beijing key laboratory of airborne particulate matter monitoring technology Beijing Municipal Environmental Monitoring CenterBeijing100048China

The source-receptor matrix of PM_(2.5)concentration from local and regional sources in the beijing-Tianjin-Hebei(BTH)and surrounding provinces has been created in previous ***,because the spatial distribution of concentration does not necessarily match with that of the population,such concentration-based source-receptor matrix may not fully reflect the importance of pollutant control effectiveness in reducing the PM_(2.5)-related health *** demonstrate that,we study the source-receptor matrix of the PM_(2.5)-related deaths instead,with inclusion of the spatial correlations between the concentrations and the *** advanced source apportionment numerical model combined with the integrated exposure-response functions is used for BTH and surrounding regions in *** observed that the relative contribution to PM_(2.5)-related deaths of local emissions was 0.75%to 20.77%larger than that of PM_(2.5)*** results address the importance of local emissions control for reducing health impacts of PM_(2.5)particularly for local *** of regional transport to PM_(2.5)-related deaths in rural area was 22%larger than that in urban area due to the spatial pattern of regional transport which was more related to the rural *** resulted in an environmental inequality in the sense that people staying in rural area with access to less educational resources are subjected to higher impacts from regional transport as compared with their more resourceful and knowledgeable urban *** unexpected benefit from the multi-regional joint controls is suggested for its effectiveness in reducing the regional transport of PM_(2.5)pollution thus mitigating the associated environmental inequality.

关键词： PM_(2.5) Regional transport Local emissions Health impact Environmental inequality

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Enhanced secondary pollution offset reduction of primary emissions during COVID-19 lockdown in China

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National Science Review 2021年第2期8卷 51-59页

作者： Xin Huang Aijun Ding Jian Gao Bo Zheng Derong Zhou Ximeng Qi Rong Tang Jiaping Wang Chuanhua Ren Wei Nie Xuguang Chi Zheng Xu Liangduo Chen Yuanyuan Li Fei Che Nini Pang Haikun Wang Dan Tong Wei Qin Wei Cheng Weijing Liu Qingyan Fu Baoxian Liu Fahe Chai Steven J.Davis Qiang Zhang Kebin He School of Atmospheric Sciences Nanjing University Chinese Research Academy of Environmental Sciences Department of Earth System Science Tsinghua University State key Joint laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua University Department of Earth System Science University of California Jiangsu Environmental monitoring Center Jiangsu Provincial Academy of Environment Science Shanghai Environmental monitoring Center beijing key laboratory of airborne particulate matter monitoring technology Beijing Municipal Environmental Monitoring Center

To control the spread of the 2019 novel coronavirus(COVID-19), China imposed nationwide restrictions on the movement of its population(lockdown) after the Chinese New Year of 2020, leading to large reductions in economic activities and associated emissions. Despite such large decreases in primary pollution, there were nonetheless several periods of heavy haze pollution in eastern China, raising questions about the well-established relationship between human activities and air quality. Here, using comprehensive measurements and modeling, we show that the haze during the COVID lockdown was driven by enhancements of secondary pollution. In particular, large decreases in NOx emissions from transportation increased ozone and nighttime NO3radical formation, and these increases in atmospheric oxidizing capacity in turn facilitated the formation of secondary particulate matter. Our results, afforded by the tragic natural experiment of the COVID-19 pandemic, indicate that haze mitigation depends upon a coordinated and balanced strategy for controlling multiple pollutants.

关键词： COVID-19 haze pollution ozone emission reduction secondary pollution

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Annual nonmethane hydrocarbon trends in beijing from 2000 to 2019

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Journal of Environmental Sciences 2022年第2期34卷 210-217页

作者： Dan Yao Guiqian Tang Jie Sun Yinghong Wang Yuan Yang Yiming Wang Baoxian Liu Hong He Yuesi Wang Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China State key laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China State key Joint laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China School of Environment Tsinghua UniversityBeijing 100084China beijing key laboratory of airborne particulate matter monitoring technology Beijing Municipal Environmental Monitoring CenterBeijing 100048China Uniuersity of Chinese Academy of Sciences Beijing 100049China

High loads of ground-level ozone have occurred with the implementation of the Air Pollution Prevention and Control Action ***,the long temporal variation in precursor nonmethane hydrocarbons(NMHCs)has rarely been *** this study,we examined the evolution of NMHCs in beijing based on ambient measurements from 2000 to *** results indicated that the annual variation of ambient NMHCs during 2000 and 2019 could be divided into two *** mixing ratios of NMHCs rapidly rose during 2000 and 2009(1.76 ppbv/year)but exhibited a downward trend from 2009 to 2019 at rate of 0.80 ppbv/***,the notable decrease in alkenes and aromatics after 2009 led to a sharp decrease in the propylene-equivalent concentration(PEC)(-0.80 ppbv/year).Implementation of emission reduction measures in beijing have effectively reduced the contribution of vehicle-related sources,but the contribution of solvent usage and fuel consumption increased,which will become the focus of VOC control in beijing in the future.

关键词： beijing NMHCs Reactivity Temporal variation

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Evaluation and Evolution of MAX-DOAS-observed Vertical NO_(2) Profiles in Urban beijing

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Advances in Atmospheric Sciences 2021年第7期38卷 1188-1196页

作者： Yanyu KANG Guiqian TANG Qihua LI Baoxian LIU Jianfeng CAO Qihou HU Yuesi WANG Institutes of Physical Science and Information technology Anhui UniversityHefei 230601China State key laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry(LAPC) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China School of Environment Tsinghua UniversityBeijing 100084China beijing key laboratory of airborne particulate matter monitoring technology Beijing Municipal Environmental Monitoring CenterBeijing 100048China Tai’an Eco-environmental monitoring Center of Shandong Province Tai’an 271000China Hefei Institute of Material Science Chinese Academy of SciencesHefei 230031China University of Chinese Academy of Sciences Beijing 100049China

Multiaxis differential absorption spectroscopy(MAX-DOAS)is a newly developed advanced vertical profile detection method,but the vertical nitrogen dioxide(NO_(2))profiles measured by MAX-DOAS have not yet been fully *** this study,we perform MAX-DOAS and tower gradient observations to simultaneously acquire tropospheric NO_(2)observations in the beijing urban area from 1 April to 31 May *** average values of the tropospheric NO_(2)vertical column densities measured by MAX-DOAS and the tropospheric monitoring instrument are 15.8×1015 and 12.4×1015 molecules cm−2,respectively,and the correlation coefficient R reaches *** MAX-DOAS measurements are highly consistent with the tower-based in situ measurements,and the correlation coefficients R from the ground to the upper air are 0.89(60 m),0.87(160 m),and 0.76(280 m).MAX-DOAS accurately measures the trend of NO_(2)vertical profile changes,although a large underestimation occurs by a factor of *** analyzing the NO_(2)vertical profile,the NO_(2)concentration reveals an exponential decrease with *** NO_(2)vertical profile also coincides with the evolution of the boundary layer *** study shows that the NO_(2)over beijing mainly originates from local sources and occurs in the boundary layer,and its vertical evolution pattern has an important guiding significance to better understand nitrate production and ozone pollution.

关键词： MAX-DOAS NO_(2) tower-based in situ observation TROPOMI validation vertical

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A monitoring-modeling approach to SO_4^(2-) and NO_3^- secondary conversion ratio estimation during haze periods in beijing, China

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Journal of Environmental Sciences 2019年第4期31卷 293-302页

作者： Xiaoqi Wang Wei Wei Shuiyuan Cheng Chong Zhang Wenjiao Duan key laboratory of beijing on Regional Air Pollution Control Beijing University of Technology Collaborative Innovation Center of beijing City Traffic Beijing University of Technology

SO_4^(2-) and NO_3^- are important chemical components of fine particulate matter(PM_(2.5)),especially during haze *** study selected two haze episodes in beijing,China with similar meteorological conditions.A monitoring-modeling approach was developed to estimate the secondary conversion ratios of sulfur and nitrogen based on monitored and simulated *** showed that in Episode 1(24th–25th October,2014),the concentrations(proportions)of SO_4^(2-) and NO_3^- reached 35.1μg/m^3(14.9%) and 55.0μg/m^3(22.9%),while they reached 14.4μg/m^3(9.3%) and 59.1μg/m^3(38.1%)in Episode 2(26th–27th October,2017).A modeling system was applied to apportion beijing's SO_4^(2-) and NO_3^- in primary and secondary SO_4^(2-)/NO_3^- emitted from local and regional ***,secondary conversion contributions considering the local and regional level were *** former primarily focused on beijing atmospheric oxidation ability and the latter mainly considered the existence form of beijing SO_4^(2-)/NO_3^- under the regional transport ***,secondary oxidation ratios were estimated through combining secondary conversion contribution coefficients for simulated and monitored *** regional level,sulfur oxidation ratios in polluted(clean)days during two sampling periods were0.57–0.72(0.07–0.52)and 0.74–0.80(0.08–0.61),nitrogen oxidation ratios were 0.20–0.29(0.05–0.15)and 0.34–0.38(0.02–0.29),indicating that atmospheric oxidation was enhanced when considering regional transport through 2014–*** the local level,sulfur oxidation ratios were 0.66–0.71(0.04–0.48)in haze(clean)days,while nitrogen oxidation ratios were0.16–0.29(0.02–0.16).The atmospheric oxidation ability markedly increased in PM_(2.5)pollution days,but changed only slightly between the two periods.

关键词： Haze periods SO42- and NO3- Secondary conversion Secondary oxidation ratio

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Size-resolved aerosol water-soluble ions at a regional background station of beijing, Tianjin, and Hebei, North China

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Journal of Environmental Sciences 2017年第5期29卷 146-156页

作者： Yongjie Yang Rui Zhou Yue Yu Yan Yan Yan Liu Yi'an Di Dan Wu Weiqi Zhang National Research Center for Environmental Analysis and Measurement Beijing 100029 China key laboratory of Atmospheric Environment monitoring and Pollution Control School of Environmental Science and Engineering Nanjing University of Information Science and Technology Nanjing 210044 China State key laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental Sciences Beijing 100012 China

The characteristics of water-soluble ions in size-resolved particulate matter were investigated usingion chromatography at Shangdianzi, a regional background station of beijing, Tianjin, and Hebei. Seasonal total concentrations of ions （Na＋, Mg2＋, IC, Ca2＋, NH＋4, Cl-, SO2-4 and NO-3） were 75.5 ± 52.9 μg/m3 in spring, 26.5 ± 12.3 Bg/m3 in summer, 22.7 ± 20.4 μg/m3 in autumn, and 31.1 ± 23.9 μg/m3 in winter, respectively. The secondary ions （NO3, SO2-4 and NH＋4）, mainly associated with fine particles, accounted for 84.2% in spring, 82.1% in summer, 81.5% in autumn and 76.3% in winter of all ions. Strong correlations were found between NH＋4 and SO2-4 （r = 0.95, p 〈 0.01） as well as NH＋4 and NO-3 （r = 0.90, p 〈 0.01） in fine particles; while in coarse particles, correlations between Mg2＋ and NO-3 （r = 0.80, p 〈 0.01）, and Ca2＋ and NO2＋（r = 0.85, p 〈 0.01） were found. The concentrations of Na＋, IC, Mg2＋, Ca2＋, NH＋4, Cl-, NO3, and SC2-4 were 2.02, 0.81, 0.36, 1.65, 9.58, 4.01, 18.9, and 18.4 μg/m3 in particulate matter from southeast-derived air masses, which were typically 1.58-3.37 times higher than in northwest trajectories. Thus, concentrations of water-soluble ions at this background station were heavily influenced by regional transport of serious pollution derived from biomass burning, coal combustion, industrial and vehicle exhaust emissions from beijing, Tianjin, and Hebei.

关键词： Water-soluble ions particulate matter Seasonal variation Size-resolved fractions Regional transport

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‘Aerosol optical properties under different pollution levels in the pearl river delta(PRD)region of China’***.87(2020)49–59

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Journal of Environmental Sciences 2021年第1期33卷 182-187页

作者： Liuwei Kong Min Hu Qinwen Tan Miao Feng Yu Qu Junling An Yuanhang Zhang Xingang Liu Nianliang Cheng State key laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing 100875China College of Environmental Sciences and Engineering Peking UniversityBeijing 100871China Chengdu Academy of Environmental Sciences Chengdu 610072China State key laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China beijing Municipal Environmental monitoring Center Beijing 100048China

The authors regret 详细信息

The authors regret

关键词： pollution aerosol revised

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Advanced modeling of the absorption enhancement of black carbon particles in chamber experiments by considering the morphology and coating thickness

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Frontiers of Environmental Science & Engineering 2024年第9期18卷 129-142页

作者： Xiaodong Wei Jianlin Hu Chao Liu Xiaodong Xie Junjie Yin Song Guo Min Hu Jianfei Peng Huijun Wang Jiangsu key laboratory of Atmospheric Environment monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and EngineeringNanjing University of Information Science&TechnologyNanjing 210044China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Key Laboratory of Meteorological Disaster(Ministry of Education)Nanjing University of Information Science and TechnologyNanjing 210044China Nansen−Zhu International Research Centre Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China East China Air Traffic Management Bureau CAAC Shanghai 200335China State key Joint laboratory of Environmental Simulation and Pollution Control International Joint Laboratory for Regional Pollution Control(IJRC)(Ministry of Education)College of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China Tianjin key laboratory of Urban Transport Emission Research&State Environmental Protection key laboratory of Urban Ambient Air particulate matter Pollution Prevention and Control College of Environmental Science and EngineeringNankai UniversityTianjin 300071China

Measurements studies have shown that the absorption of radiation by black carbon(BC)increases as the particles ***,there are significant discrepancies between the measured and modeled absorption enhancement(E_(abs)),largely due to the simplifications used in modeling the mixing states and shape *** took advantage of chamber experiments on BC aging and developed an efficient method to resolve the particle shape based on the relationship between the coating fraction(ΔD_(ve)/D_(ve),0)and fractal dimension(D_(f)),which can also reflect the variations of D_(f)during the whole BC aging *** with externally and partly mixed states(0≤ΔD_(ve)/D_(ve),0≤0.5)can be considered to be uniformly distributed with the D_(f)values of 1.8–2.1,whereas the Df values are constrained in the range 2.2–2.8 for fully mixed states(ΔD_(ve)/D_(ve),0>0.5).The morphological parameters(i.e.,the effective density and the dynamic shape factor)were compared with the measured values to verify the simulated *** simulated mean deviations of morphological parameters were smaller than 8%for the method resolving the particle *** applying a realistic shape and refractive index,the mass absorption cross for fully mixed states can be improved by 11%compared with a simplified core–shell *** on our understanding of the influence of D_(f)andΔD_(ve)/D_(ve),0 on E_(abs),we propose a two-stage calibration equation to correct the E_(abs)values estimated by the core–shell model,which reduces the simulation error in the Mie calculation by 6%–14%.

关键词： Black carbon Mixing states Fractal dimension Dynamic shape factor Absorption enhancement

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