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A spectrometer for measuring particle size distributions in the range of 3 nm to 10 μm

Frontiers of environmental Science & Engineering 2016年第1期10卷 63-72页

作者： Jieqiong LIU Jingkun JIANG Qiang ZHANG Jianguo DENG Jiming HAO State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Beijing 100084 China

A spectrometer combining electrical mobility sizing and aerodynamic sizing was developed to measure aerosol size distributions in the range of 3 nm to 10 μm. It includes three instruments which cover different size ranges （a nano scanning mobility particle sizer （NSMPS, 3 - 60 nm）, a regular scanning mobility particle sizer （RSMPS, 40 - 700nm）, and an aerodynamic particle sizer （APS, 550nm- 10 μm））. High voltage and sheath flow of the NSMPS and RSMPS were supplied using two home-built control boxes. A LabVIEW program was developed for spectrometer automatic operation. A linear inversion method was applied to correct particle multiple charging effects and to integrate data from the three instruments into a wide-range size distribution. Experi- ments were conducted to compare distributions in the overlap size ranges measured by three instruments. Good agreement between the NSMPS and RSMPS was achieved after correcting for the difference in counting efficiencies of the two particle counters. Aerodynamic size distribu- tions reported by the APS were converted to mobility size distributions by applying an effective density method. Distributions measured by the RSMPS and APS were consistent in the overlap size range of 550 - 700 nm. A full spectrum in the size range of 3nm to 10~tm was demonstrated by measuring aerosol generated using a mixture of different sized polystyrene latex spheres.

关键词： spectrometer particle size distribution elec-trical mobility aerodynamic diameter linear inversion

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Mercury mass flow in iron and steel production process and its implications for mercury emission control

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Journal of environmental Sciences 2016年第5期28卷 293-301页

作者： Fengyang Wang Shuxiao Wang Lei Zhang Hai Yang Wei Gao Qingru Wu Jiming Hao State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua UniversityBeijing 100084 China State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Beijing 100084 China

The iron and steel production process is one of the predominant anthropogenic sources of atmospheric mercury emissions worldwide. In this study, field tests were conducted to study mercury emission characteristics and mass flows at two iron and steel plants in China. It was found that low-sulfur flue gas from sintering machines could contribute up to41% of the total atmospheric mercury emissions, and desulfurization devices could remarkably help reduce the emissions. Coal gas burning accounted for 17%–49% of the total mercury emissions, and therefore the mercury control of coal gas burning, specifically for the power plant burning coal gas to generate electricity, was significantly important. The emissions from limestone and dolomite production and electric furnaces can contribute29.3% and 4.2% of the total mercury emissions from iron and steel production. More attention should be paid to mercury emissions from these two processes. Blast furnace dust accounted for 27%–36% of the total mercury output for the whole iron and steel production process. The recycling of blast furnace dust could greatly increase the atmospheric mercury emissions and should not be conducted. The mercury emission factors for the coke oven,sintering machine and blast furnace were 0.039–0.047 g Hg/ton steel, and for the electric furnace it was 0.021 g Hg/ton steel. The predominant emission species was oxidized mercury, accounting for 59%–73% of total mercury emissions to air.

关键词： Iron and steel plant Mercury Emission characteristics Mass flow Emission control

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A review of atmospheric mercury emissions, pollution and control in China

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Frontiers of environmental Science & Engineering 2014年第5期8卷 631-649页

作者： Shuxiao WANG Lei ZHANG Long WANG Qingru WU FengyangWANG Jiming HAO State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Beijing 100084 China

Mercury, as a global pollutant, has significant impacts on the environment and human health. The current state of atmospheric mercury emissions, pollution and control in China is comprehensively reviewed in this paper. With about 500-800 t of anthropogenic mercury emissions, China contributes 25%-40% to the global mercury emissions. The dominant mercury emission sources in China are coal combustion, non-ferrous metal smelting, cement production and iron and steel production. The mercury emissions from natural sources in China are equivalent to the anthropogenic mercury emissions. The atmospheric mercury concentration in China is about 2-10 times the background level of North Hemisphere. The mercury deposition fluxes in remote areas in China are usually in the range of 10-50μg·m^-2·yr^-1. To reduce mercury emissions, legislations have been enacted for power plants, non-ferrous metal smelters and waste incinerators. Currently mercury contented in the flue gas is mainly removed through existing air pollution control devices for sulfur dioxide, nitrogen oxides, and particles. Dedicated mercury control technologies are required in the future to further mitigate the mercury emissions in China.

关键词： atmospheric mercury emissions pollution,control China

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Efectiveness of national air pollution control policies on the air quality in metropolitan areas of China

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Journal of environmental Sciences 2014年第1期26卷 13-22页

作者： Shuxiao Wang Jia Xing Bin Zhao Carey Jang Jiming Hao State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex US Environmental Protection Agency Research Triangle Park Collaborative Innovation Center for Regional Environmental Quality Tsinghua University

Understanding the effectiveness of national air pollution controls is important for control policy design to improve the future air quality in China. This study evaluated the effectiveness of major national control policies implemented recently in China through a modeling analysis. The sulfur dioxide （SO2） control policy during the llth Five Year Plan period （2006-2010） had succeeded in reducing the national SO2 emission in 2010 by 14% from its 2005 level, which correspondingly reduced ambient SO2 and sulfate （SO42-） concentrations by 13%-15% and 8%-10% respectively over east China. The nitrogen oxides （NOx） control policy during the 12th Five Year Plan period （2011-2015） targets the reduction of the national NOx emission in 2015 by 10% on the basis of 2010. The simulation results suggest that such a reduction in NOx emission will reduce the ambient nitrogen dioxide （NO2）, nitrate （NO3-）, 1-hr maxima ozone （03） concentrations and total nitrogen deposition by 8%, 3%-14%, 2% and 2%--4%, respectively over east China. The application of new emission standards for power plants will further reduce the NO2, NO3-, 1-hr maxima 03 concentrations and total nitrogen deposition by 2%-4%, 1%-%, 0-2% and 1%-2%, respectively. Sensitivity analysis was conducted to evaluate the inter-provincial impacts of emission reduction in Beijing-Tianjin-Hebei and the Yangtze River Delta, which indicated the need to implement joint regional air pollution control.

关键词： air pollution control sulfur dioxide nitrogen oxides power plant

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PM2.5 concentration estimation using convolutional neural network and gradient boosting machine

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Journal of environmental Sciences 2020年第12期32卷 85-93页

作者： Zhenyu Luo Feifan Huang Huan Liu State Key Joint Laboratory of ESPC School of the EnvironmentTsinghua UniversityBeijing 100084China State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Beijing 100084China

Surface monitoring, vertical atmospheric column observation, and simulation using chemical transportation models are three dominant approaches for perception of fine particles with diameters less than 2.5 micrometers(PM2.5) concentration. Here we explored an imagebased methodology with a deep learning approach and machine learning approach to extend the ability on PM2.5 perception. Using 6976 images combined with daily weather conditions and hourly time data in Shanghai(2016), trained by hourly surface monitoring concentrations, an end-to-end model consisting of convolutional neural network and gradient boosting machine(GBM) was constructed. The mean absolute error, the root-mean-square error and the R-squared for PM2.5 concentration estimation using our proposed method is 3.56, 10.02, and 0.85 respectively. The transferability analysis showed that networks trained in Shanghai, fine-tuned with only 10% of images in other locations, achieved performances similar to ones from trained on data from target locations themselves. The sensitivity of different regions in the image to PM2.5 concentration was also quantified through the analysis of feature importance in GBM. All the required inputs in this study are commonly available, which greatly improved the accessibility of PM2.5 concentration for placed and period with no surface observation. And this study makes an exploratory attempt on pollution monitoring using graph theory and deep learning approach.

关键词： Deep learning Convolutional neural network Hybrid model PM2.5concentration

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Physicochemical analysis of individual atmospheric fine particles based on effective surface-enhanced Raman spectroscopy

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Journal of environmental Sciences 2019年第1期31卷 388-395页

作者： Zhenli Sun Fengkui Duan Kebin He Jingjing Du Liu Yang Hui Li Tao Ma Shuo Yang State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Tsinghua University State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences

Fine particles associated with haze pollution threaten the health of more than 400 million people in China. It is therefore of great importance to thoroughly investigate and understand their composition. To determine the physicochemical properties in atmospheric fine particles at the micrometer level, we described a sensitive and feasible surface-enhanced Raman scattering(SERS) method using Ag foil as a substrate. This novel method enhanced the Raman signal intensities up to 10,000 a.u. for ν(NO_3^-) in fine *** SERS effect of Ag foil was further studied experimentally and theoretically and found to have an enhancement factor of the order of ～10~4. Size-fractionated real particle samples with aerodynamic diameters of 0.4–2.5 μm were successfully collected on a heavy haze day,allowing ready observation of morphology and identification of chemical components, such as soot, nitrates, and sulfates. These results suggest that the Ag-foil-based SERS technique can be effectively used to determine the microscopic characteristics of individual fine particles, which will help to understand haze formation mechanisms and formulate governance policies.

关键词： SERS PM2.5 Individual particle Atmospheric

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Progress of air pollution control in China and Its Challenges and Opportunities in the Ecological Civilization Era

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Engineering 2020年第12期6卷 1423-1431页

作者： Xi Lu Shaojun Zhang Jia Xing Yunjie Wang Wenhui Chen Dian Ding Ye Wu Shuxiao Wang Lei Duan Jiming Hao State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Beijing 100084China

China’s past economic growth has substantially relied on fossil fuels,causing serious air pollution *** economic growth and pollution has become the focus in developing ecological civilization in *** have analyzed the three-decade progress of air pollution controls in China,highlighting a strategic transformation from emission control toward air quality *** control of sulfur dioxide(SO2)resolved the deteriorating acid rain issue in China in *** 2013,control actions on multiple precursors and sectors have targeted the reduction of the concentration of fine particulate matter(PM2.5),marking a transition to an air-quality-oriented *** ozone(O3)pollution further requires O3 and PM2.5 integrated control strategies with an emphasis on their complex photochemical *** improvement of air quality in China,as a key indicator for the success of ecological civilization construction,demands the deep de-carbonization of China’s energy system as well as more synergistic pathways to address air pollution and global climate change simultaneously.

关键词： air pollution control Ecological civilization PM2.5 Low-carbon development Ozone

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Spatial and temporal variation of haze in China from 1961 to 2012

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Journal of environmental Sciences 2016年第8期28卷 134-146页

作者： Rui Han Shuxiao Wang Wenhai Shen Jiandong Wang Kang Wu Zhihua Ren Mingnong Feng National Meteorological Information Center China Meteorological Administration State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Department of Precision Instrument Tsinghua University

The purpose of this study is to analyze the climatic characteristics and long-term spatial and temporal variations of haze occurrence in China. The impact factors of haze trends are also discussed. Meteorological data from 1961 to 2012 and daily PM10 concentrations from2003 to 2012 were employed in this study. The results indicate that the annual-average hazy days at all stations have been increasing rapidly from 4 days in 1961 to 18 days in 2012. The maximum number of haze days occur in winter（41.1%） while the minimum occur in summer（10.4%）. During 1961-2012, the high occurrence areas of haze shifted from central to south and east regions of China. The Beijing-Tianjin-Hebei（Jing-Jin-Ji） region, Shanxi,Shaanxi, and Henan Province are the high occurrence areas for haze, while the Yangtze River Delta（YRD） and the Pearl River Delta（PRD） have become regions with high haze occurrences in the last 25 years. Temperature and pressure are positively correlated with the number of haze days. However, wind, relative humidity, precipitation, and sunshine duration are negatively correlated with the number of haze days. The key meteorological factors affecting the formation and dissipation of haze vary for high and low altitudes, and are closely related to anthropogenic activities. In recent years, anthropogenic activities have played a more important role in haze occurrences compared with meteorological factors.

关键词： China Haze Spatial distribution Interannual trend Meteorological factors Anthropogenic activities

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Altitude-dependent gaseous emissions from freight trucks along the China-Pakistan Economic Corridor in Pakistan

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environmental Science and Ecotechnology 2023年第2期14卷 72-78页

作者： Asad Ali Shaikh Tingkun He Fanyuan Deng Zhenyu Luo Junchao Zhao Zhining Zhang Huan Liu State Key Joint Laboratory of ESPC State Environmental Protection Key Laboratory of Sources and Control of Air Pollution ComplexSchool of EnvironmentTsinghua UniversityBeijing100084China

Recent increases in emissions from freight transport have caused strong concerns about air quality in Pakistan,following the rapid development of projects related to the China-Pakistan Economic Corridor(CPEC).This study reported the first measurements of on-road truck emissions in Pakistan and investigated their dependence on altitude along CPEC *** from 70 trucks were measured on CPEC highways located in Islamabad(540 m above sea level),Sost(2800 m above sea level),and at the Khunjerab Pass(4693 m above sea level).Calculated emission factors for carbon monoxide,hydrocarbons,and nitrogen oxides from heavy-duty trucks in Islamabad were 12.94±1.46,15.21±1.67,and 10.69±1.34 g km^(-1)(95%confidence level),respectively,for pre-Pak-II trucks,and 12.75±2.80,14.24±3.53,and 10.24±2.34 g km^(-1)(95%confidence level),respectively,for Pak-II trucks,representing 2e20 times higher values than the emission standards in Pakistan and *** altitude increase of approximately 4000 m,with the associated changes in meteorology and fleet characteristics,induced an average increase of 103.6%,86.3%,124.5%,and 133.6%in the emission factors of carbon monoxide,hydrocarbons,nitrogen oxides,and carbon dioxide,***,on-road emissions along the CPEC were mainly influenced by truck *** study will support the budget evaluation of transport emissions from the CPEC trade fleet.

关键词： Truck emissions High altitude China-Pakistan Economic corridor Emission factors

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Local and regional contributions to PM_(2.5) in the Beijing 2022 Winter Olympics infrastructure areas during haze episodes

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Frontiers of environmental Science & Engineering 2021年第6期15卷 499-509页

作者： Yue Wang Mengshuang Shi Zhaofeng Lv Huan Liu Kebin He State Key Joint Laboratory of ESPC State Environmental Protection Key Laboratory of Sources and Control of Air Pollution ComplexInternational Joint Laboratory on Low Carbon Clean Energy InnovationSchool of the EnvironmentTsinghua UniversityBeijing 100084China

The 2022 Winter Olympics is scheduled to take place in Beijing and Zhangjiakou,which were defined as OIAs(Olympic infirastructure areas)in this *** study presents the characteristics and source apportionment of PM_(2.5) in the OIAs,*** entire region of China's Mainland,except for the OIAs,was divided into 9 source regions,including four regions in the BTH(Beijing-Tianjin-Hebei)region,the four provinces surrounding the BTH and the remaining *** CAMx/PSAT,the contributions of the nine regions to the PM_(2.5) concentration in the OIAs were simulated spatially and *** simulated source apportionment results showed that the contribution of regional transportation was 48.78%,and when PM_(2.5) concentration was larger than 75μg/m^(3) central Hebei was the largest contributor with a contribution of 19.18%,followed by Tianjin,northern Hebei,Shanxi,Inner Mongolia,Shandong,southern Hebei,Henan and ***,the contribution from neighboring regions of the OIAs was 47.12%,which was nearly twice that of long-range *** episodes were analyzed,and the results presented the importance of regional transportation during severe PM_(2.5) pollution *** was also found that they were associated with differences in pollution sources between Zhangjiakou and *** transportation was the main factor affecting PM_(2.5) pollution in Zhangjiakou due to its low local *** weather with a low planetary boundary layer height and a low wind velocity prevented the local emitted pollutants in Beijing from being transported outside,and as a result,local emissions constituted a larger contribution in Beijing.

关键词： 2022 Winter Olympics PM_(2.5) Source apportionment

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