Black carbon (BC) aerosols are considered key factors that contribute to rapid climate warming and ice melt in the Arctic region.However,compared with long-term observations from land-based stations,observational data...Black carbon (BC) aerosols are considered key factors that contribute to rapid climate warming and ice melt in the Arctic region.However,compared with long-term observations from land-based stations,observational data over the Arctic Ocean remain relatively scarce.Four Arctic scientific expeditions were conducted in the summer and early autumn of 2010,2012,2016,and 2018 via the Chinese research vessel Xue Long,during which the BC concentrations along the routes were measured via light absorption methods.In this work,the spatiotemporal distribution characteristics of BC over the Arctic Ocean were examined on the basis of these observations.The potential sources of BC along the various routes were analyzed via the weighted potential source contribution function and weighted concentrationweighted trajectory methods of the hybrid single-particle Lagrangian integrated trajectory model in conjunction with Arctic transport potential climate model simulations.The analysis results indicated that wildfires in the western Aleutian Islands,Siberia,and Far East regions were the primary contributors to the BC aerosol concentration observed along the Arctic expedition routes in summer,identifying these regions as major potential source areas.展开更多
This study tracked the characteristics of atmospheric wet deposition of the toxic element arsenic(As)at both urban(Guangzhou(GZ))and forested(Dinghushan Natural Reserve(DHS))sites within the Pearl River Delta(PRD)regi...This study tracked the characteristics of atmospheric wet deposition of the toxic element arsenic(As)at both urban(Guangzhou(GZ))and forested(Dinghushan Natural Reserve(DHS))sites within the Pearl River Delta(PRD)region between 2016 and 2019,examining its correlation with rainfall patterns.Additionally,by employing backward trajectory analysis and the potential source contribution function(PSCF)in conjunction with pertinent emission inventories,we pinpointed the main pathways of atmospheric arsenic transport and evaluated the emission contributions from priority source areas.The study revealed that the atmospheric arsenic wet deposition fluxes at the GZ and DHS sites exhibited a trend of increase followed by a decrease over the four-year period.Wet season deposition fluxes were more than triple those of the dry season,with urban site showing a difference of over four times.Notably,wet season As deposition at both sites was predominantly affected by heavy rainfall from marine air masses,constituting 31%of the total deposition.The predominant trajectory directions contributing to arsenic deposition at GZ and DHS were northeast(55%)and south(53%),respectively.The primary source areas for both sites were largely outside the PRD region,with the GZ site having 80%to 95%of its source area in the non-PRD region,compared to 69%to 88%at the DHS site.Furthermore,non-PRD areas contributed approximately 65%to arsenic emissions for both sites,with the industrial sector being the dominant emission source,exceeding 97%of the total emissions.展开更多
A distinctive kind of organic carbon aerosol that could absorb ultraviolet-visible radiation is called brown carbon(Br C),which has an important positive influence on radiative budget and climate change.In this work,w...A distinctive kind of organic carbon aerosol that could absorb ultraviolet-visible radiation is called brown carbon(Br C),which has an important positive influence on radiative budget and climate change.In this work,we reported the absorption properties and potential source of Br C based on a seven-wavelength aethalometer in the winter of 2018–2019 at an urban site of Sanmenxia in Fenwei Plain in central China.Specifically,the mean value of Br C absorption coefficient was 59.6±36.0 Mm^(-1) at 370 nm and contributed 37.7%to total absorption,which made a significant impact on visibility and regional environment.Absorption coefficients of Br C showed double-peak pattern,and Br C had shown small fluctuations under haze days compared with clean days.As for the sources of Br C,Br C absorption coefficients expressed strong correlations with element carbon aerosols and primary organic carbon aerosols,indicating that most of Br C originated from primary emissions.The linear correlations between trace metal elements(K,As,Fe,Mn,Zn,and Pb)and Br C absorption coefficients further referred that the major sources of Br C were primary emissions,like coal burning,biomass burning,and vehicle emissions.The moderate relationship between Br C absorption coefficients and secondary organic aerosols suggested that secondary production of Br C also played an important role.The 120 hr backward air mass trajectories analysis and concentration-weighted trajectories analysis were also used to investigate potential sources of Br C in and around this area,which inferred most parts of Br C were derived from local emissions.展开更多
This study attempts to identify the dominant transport pathways,potential source areas,and their seasonal variation at sites with high inorganic nitrogen(IN)wet deposition flux in southern China.This is a long-term st...This study attempts to identify the dominant transport pathways,potential source areas,and their seasonal variation at sites with high inorganic nitrogen(IN)wet deposition flux in southern China.This is a long-term study(2010-2017)based on continuous deposition measurements at the Guangzhou urban site(GZ)and the Dinghushan Natural Reserve site(DHS)located in the Pearl River Delta(PRD)region.A dataset on monthly IN concentration in precipitation and wet deposition flux were provided.The average annual fluxes measured at both sites(GZ:33.04±9.52,DHS:20.52±10.22 kg N/(ha·year))were higher,while the ratios of reduced to oxidized N(GZ:1.19±0.77,DHS:1.25±0.84)were lower compared with the national mean level and the previous reported level throughout the PRD region.The dominant pathways were not always consistent with the highest proportional trajectory clusters.The transport pathways contributing most of deposition were identified in the north and northnortheast in the dry season and in the east-southeast,east,and south-southwest in the wet season.A weighted potential source contribution function(WPSCF)value>0.3 was determined reasonably to define the potential source area.Emission within the PRD region contributed the majority(≥95%at both sites)of the IN deposition in the wet season,while the contribution outside the region increased significantly in the dry season(GZ:27.86%,DHS:95.26%).Our results could help create more effective policy to control precursor emissions for IN fluxes,enabling reduction of the ecological risks due to excessive nitrogen.展开更多
Based on one-year observation,the concentration,sources,and potential source areas of volatile organic compounds(VOCs)were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haiko...Based on one-year observation,the concentration,sources,and potential source areas of volatile organic compounds(VOCs)were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haikou,China.The results showed that the annual average concentration of total VOCs(TVOCs)was 11.4 ppb V,and the composition was dominated by alkanes(8.2 ppb V,71.4%)and alkenes(1.3 ppb V,20.5%).The diurnal variation in the concentration of dominant VOC species showed a distinct bimodal distribution with peaks in the morning and evening.The greatest contribution to ozone formation potential(OFP)was made by alkenes(51.6%),followed by alkanes(27.2%).The concentrations of VOCs and nitrogen dioxide(NO_(2))in spring and summer were low,and it was difficult to generate high ozone(O_(3))concentrations through photochemical reactions.The significant increase in O_(3)concentrations in autumn and winter was mainly related to the transmission of pollutants from the northeast.Traffic sources(40.1%),industrial sources(19.4%),combustion sources(18.6%),solvent usage sources(15.5%)and plant sources(6.4%)were identified as major sources of VOCs through the positive matrix factorization(PMF)model.The southeastern coastal areas of China were identified as major potential source areas of VOCs through the potential source contribution function(PSCF)and concentration-weighted trajectory(CWT)models.Overall,the concentration of ambient VOCs in Haikou was strongly influenced by traffic sources and long-distance transport,and the control of VOCs emitted from vehicles should be strengthened to reduce the active species of ambient VOCs in Haikou,thereby reducing the generation of O_(3).展开更多
Long-term stereoscopic observations of aerosol,NO2,and HCHO were carried out at the Yangmeikeng(YMK)site in Shenzhen.Aerosol optical depths and NO2 vertical column concentration(NO2 VCD)derived from MAX-DOAS were foun...Long-term stereoscopic observations of aerosol,NO2,and HCHO were carried out at the Yangmeikeng(YMK)site in Shenzhen.Aerosol optical depths and NO2 vertical column concentration(NO2 VCD)derived from MAX-DOAS were found to be consistent with other datasets.The total NO2 VCD values of the site remained low,varying from 2×10^(15)to 8×10^(15)mol/cm^(2),while the HCHO VCD was higher than NO2 VCD,varying from 7×10^(15)to 11×10^(15)mol/cm^(2).HCHO VCD was higher from September to early November than that was from mid-late November to December and during February 2021,in contrast,NO2 VCD did not change much during the same period.In January,NO2 VCD and HCHO VCD were both fluctuating drastically.High temperature and HCHO level in the YMK site is not only driving the ozone production up but alsomay be driving up the ozone concentration as well,and the O_(3)production regime in the YMK site tends to be NOx-limited.At various altitudes,backward trajectory clustering analysis and Potential Source Contribution Function(PSCF)were utilized to identify possible NO2 and HCHO source locations.The results suggested that the Huizhou-Shanwei border and the Daya Bay Sea area were the key potential source locations in the lower(200 m)and middle(500 m)atmosphere(WPSCF>0.6).The WPSCF valuewas high at the 1000maltitude whichwas closer to the YMKsite than the near ground,indicating that the pollution transport capability in the upper atmosphere was limited.展开更多
Based on the results of focal mechanism solutions in southeastern areas of China （south of 34°N and east of 105° E）, this article analyzes the correlation of focal mechanism solutions with seismogenic stru...Based on the results of focal mechanism solutions in southeastern areas of China （south of 34°N and east of 105° E）, this article analyzes the correlation of focal mechanism solutions with seismogenic structures of moderate strong earthquakes and the direction of potential source zones. The data show that the nodal planes of focal mechanism solutions and the principle stresses in southern China are of predominantly similar directions, most of the solutions for M ≥4.0 earthquakes correspond to the main structure directions as well as the directions of potential source zones. The statistical results of multiple small earthquakes concerning nodal planes and main stress axes are also reliable for determining the direction of potential source zones. According to the analysis of focal mechanism solutions, long-axis direction of isoseismals distribution of aftershocks, geologic structures, and seismic activity in two areas of the Ms6.1 earthquake in the south Yellow Sea in 1996 and the MsS.2 earthquake in Fujian in 1997, the potential source zone division is discussed.展开更多
Phthalate esters(PAEs),recognized as endocrine disruptors,are released into the environment during usage,thereby exerting adverse ecological effects.This study investigates the occurrence,sources,and risk assessment o...Phthalate esters(PAEs),recognized as endocrine disruptors,are released into the environment during usage,thereby exerting adverse ecological effects.This study investigates the occurrence,sources,and risk assessment of PAEs in surface water obtained from 36 sampling points within the Yellow River and Yangtze River basins.The total concentration of PAEs in the Yellow River spans from124.5 to 836.5 ng/L,with Dimethyl phthalate(DMP)(75.4±102.7 ng/L)and Diisobutyl phthalate(DiBP)(263.4±103.1 ng/L)emerging as the predominant types.Concentrations exhibit a pattern of upstream(512.9±202.1 ng/L)>midstream(344.5±135.3 ng/L)>downstream(177.8±46.7 ng/L).In the Yangtze River,the total concentration ranges from 81.9 to 441.6 ng/L,with DMP(46.1±23.4 ng/L),Diethyl phthalate(DEP)(93.3±45.2 ng/L),and DiBP(174.2±67.6 ng/L)as the primary components.Concentration levels follow a midstream(324.8±107.3 ng/L)>upstream(200.8±51.8 ng/L)>downstream(165.8±71.6 ng/L)pattern.Attention should be directed towards the moderate ecological risks of DiBP in the upstream of HH,and both the upstream and midstream of CJ need consideration for the moderate ecological risks associated with Di-n-octyl phthalate(DNOP).Conversely,in other regions,the associated risk with PAEs is either low or negligible.The main source of PAEs in Yellow River is attributed to the release of construction land,while in the Yangtze River Basin,it stems from the accumulation of pollutants in lakes and forests discharged into the river.These findings are instrumental for pinpointing sources of PAEs pollution and formulating control strategies in the Yellow and Yangtze Rivers,providing valuable insights for global PAEs research in other major rivers.展开更多
Water-soluble organic nitrogen(WSON)affects the formation,hygroscopicity,acidity of organic aerosols,and nitrogen biogeochemical cycles.However,qualitative and quantitative characterizations of WSON remain limited due...Water-soluble organic nitrogen(WSON)affects the formation,hygroscopicity,acidity of organic aerosols,and nitrogen biogeochemical cycles.However,qualitative and quantitative characterizations of WSON remain limited due to its chemical complexity.In the study,1-year field samples of particulate matter 2.5(PM_(2.5))were collected fromJune 2022 to May 2023 to analyze the WSON concentration in PM_(2.5),and correlation analysis,positive matrix factor(PMF),and potential source contribution function(PSCF)modelswere employed to elucidate WSON source apportionment and transport pathways.The results revealed that the mean WSON concentrations reached 1.98±2.64μg/m^(3) with a mean WSON to water-soluble total nitrogen(WSTN)ratio of 21%.Further,WSON concentration exhibited a seasonal variation trend,with higher values in winter and lower in summer.Five sources were identified as contributors to WSON in PM_(2.5) within the reservoir area through a comprehensive analysis including correlation analysis,PSCF and concentration weighted trajectory(CWT),and PMF analyses.These sources were agricultural,dust,combustion,traffic,and industrial sources,of which agricultural source emerged as the primary contributor(76.69%).The atmosphere in the reservoir area were primarily influenced by the transport of northeastern air masses,local agricultural activities,industrial cities along the trajectory,and coastal regions,exerting significant influences on the concentration of WSON in the reservoir area.The findings of this study addressed the research gap concerning organic nitrogen in PM_(2.5) within the reservoir area,thereby offering a theoretical foundation and data support in controlling nitrogen pollution in the Danjiangkou Reservoir area.展开更多
Based on the chemical composition data of a regional long-lasting haze event that occurred in the Yangtze River Delta(YRD)region from 17 December 2023 to 8 January 2024,the evolutionary characteristics of the chemical...Based on the chemical composition data of a regional long-lasting haze event that occurred in the Yangtze River Delta(YRD)region from 17 December 2023 to 8 January 2024,the evolutionary characteristics of the chemical components and sources of fine particulate matter(PM2.5)under different pollution levels were comparatively analyzed using PMF(Positive Matrix Factorization)and backward trajectory analysis.SNA(NO_(3)^(-),NH_(4)^(+),SO_(4)^(2-))was found to be the primary chemical component of PM2.5,making up 63.6%(clean days)to 69.7%(heavy pollution)of it.The NO_(3)^(-)concentration was 3.14(clean days)to 6.01(heavy pollution)times higher than that of SO_(4)^(2-).NO_(3)^(-),POC,Fe,Mn,Al concentrations increased,while SOC,EC,crustal elements(Ca,Si)and other water-soluble ions(WSIs)concentrations decreased as the pollution level increased.The contribution of secondary inorganics and biomass-burning emissions and industrial and ship emissions increased significantly as the pollution level increased,which accounted for 40.3%and 36.7%,respectively,in the heavy pollution stage.The contribution of traffic sources decreases gradually with increasing pollution levels,accounting for only 59.1%of the light pollution stage in the heavy pollution stage.PM_(2.5) and its main chemical components showed similar potential source distribution,located in the northwest(Fuyang,Huainan,Nanjing),south(Taizhou,Lishui,Jiande)and north(Taizhou,Yancheng).However,distinct transport routes were observed under the different air quality levels.During the heavy pollution period,the polluted air masses primarily came from the harbor regions,whereas during the light pollution period they were transported from the southeast(Taizhou)and the North China Plain.展开更多
Precipitation isotopes(δ^(18)O and δ^(2)H)are closely related to meteorological conditions for precipitation generation and the initial state of water vapor source areas,and are essential to the study of the regiona...Precipitation isotopes(δ^(18)O and δ^(2)H)are closely related to meteorological conditions for precipitation generation and the initial state of water vapor source areas,and are essential to the study of the regional hydrological cycle.The deuterium excess(d-excess)indicates deviation in isotope fractionation during evaporation and can trace water vapor sources.This study analyzed 443 precipitation samples collected from the Gannan Plateau,China in 2022 to assess precipitation isotope variations and their driving factors.Water vapor sources were evaluated using the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT),Concentration Weighted Trajectory(CWT),and Potential Source Contribution Factor(PSCF)models.Results showed that precipitation isotope values showed significant spatial and temporal variations on the Gannan Plateau.Temporally,precipitation isotope values peaked in June(when evaporation dominated)and minimized in March(depletion effect of air masses in the westerly wind belt).Spatially,the isotope values showed a distribution pattern of"high in the east and low in the west",which was mainly regulated by the differences in altitude and local meteorological conditions.Compared with the global meteoric water line(GMWL)with equation of δ^(2)H=8.00δ^(18)O+10.00,the slope and intercept of local meteoric water line(LMWL)for precipitation on the Gannan Plateau were smaller(7.49 and 7.63,respectively),reflecting the existence of a stronger secondary evaporation effect under the clouds in the region.The sources of water vapor on the Gannan Plateau showed significant seasonality and spatial heterogeneity.Specifically,the westerly belt and monsoon were the main water vapor transport paths at each sampling point,with Central Asian continental water vapor dominating in spring(53.49%),Indian Ocean water vapor dominating in summer(52.53%),Atlantic Ocean water vapor dominating in autumn(46.74%),and Atlantic Ocean and Mediterranean Sea water vapor dominating in winter(42.30%and 33.68%,respectively).Changes in the intensity of convective activity and Outgoing Longwave Radiation(OLR)affected the enrichment of isotopic values,which exhibited the same change trends as δ^(18)O.During the precipitation process,the δ^(18)O value first decreased and then increased.During the initial and final stages of precipitation process,precipitation was mainly influenced by continental air masses,while during the middle stage,it was controlled by marine air masses.The systematic research on precipitation isotopes and water vapor sources is important for climate change research and extreme precipitation prediction on the Gannan Plateau and other similar areas.展开更多
Magnitude and distance of major potential source are needed in order to determine duration time of artificial ground motion and to determine the type of response spectrum (near field or far field) when using the seism...Magnitude and distance of major potential source are needed in order to determine duration time of artificial ground motion and to determine the type of response spectrum (near field or far field) when using the seismic intensity zonation map. The magnitude probabilistic distribution function of seismic belt and the magnitude and space joint distribution function for given intensity of the site in a potential Source are provided. Then the basicformula of calculating expected magnitude and expected distance are developed. Several examples for calculating expected magnitude and expected distance in northern China are discussed. These results show that expected magnitude and expected distance are related not only to geometry of potential source and magnitude but also to the intensity of the site with certain exceeding probability.展开更多
In the paper, we have discovered the abnormal area distribution features of maximum variation values of ground motion parameter uncertainty with different probabilities of exceedance in 50 years within the range of 10...In the paper, we have discovered the abnormal area distribution features of maximum variation values of ground motion parameter uncertainty with different probabilities of exceedance in 50 years within the range of 100°-120°E, 29°-42°N for the purpose to solve the problem that abnormal areas of maximum variation values of ground motion parameter uncertainties emerge in a certain cities and towns caused by seismicity parameter uncertainty in a seismic statistical region in an inhomogeneous distribution model that considers tempo-spatial nonuniformity of seismic activity. And we have also approached the interrelation between the risk estimation uncertainty of a site caused by seismicity parameter uncertainty in a seismic statistical region and the delimitation of potential sources, as well as the reasons for forming abnormal areas. The results from the research indicate that the seismicity parameter uncertainty has unequal influence on the uncertainty of risk estimation at each site in a statistical region in the inhomogeneous distribution model, which relates to the scheme for delimiting potential sources. Abnormal areas of maximum variation values of ground motion parameter uncertainty often emerge in the potential sources of Mu greater than or equal 8 (Mu is upper limit of a potential source) and their vicinity. However, this kind of influence is equal in the homogeneous distribution model. The uncertainty of risk estimation of each site depends on its seat. Generally speaking, the sites located in the middle part of a statistical region are only related to the seismicity parameter uncertainty of the region, while the sites situated in or near the juncture of two or three statistical regions might be subject to the synthetic influences of seismicity parameter uncertainties of several statistical regions.展开更多
The Northern Key Economic region of Vietnam is a dynamic economic center that is an important economic locomotive of the North and the whole of Vietnam.In this area,large industrial parks are concentrated,attracting m...The Northern Key Economic region of Vietnam is a dynamic economic center that is an important economic locomotive of the North and the whole of Vietnam.In this area,large industrial parks are concentrated,attracting many large FDI projects.Key industries:cement production,cars-motorcycles,electronics,...Economic development entails environmental problems.The industrial sector has been identified as the number one driving force driving the growth of Hanoi city and neighboring provinces.Therefore,industrial development is one of the main causes of environmental pollution.In addition,the growth rate of industry in neighboring provinces significantly affects the air quality in Hanoi city.Some factories in Vinh Phuc,Hung Yen,Bac Ninh and Hai Duong provinces have large sources of gas emissions,potentially affecting air quality around Hanoi city.Monitoring results show that air pollution in Hanoi city is mainly caused by dust pollution,especially PM2.5 superfine dust.This is a very harmful dust to health;it is necessary to determine the cause and control solution.Therefore,the objectives of this study are:(1)inventory of potential emissions sources for industrial activities in the northern key economic region around Hanoi;(2)Simulate air spread by AERMOD model to get an overall picture of the industrial impact of surrounding provinces in Hanoi city;(3)Propose solutions to manage air quality for the city in the coming time.Simulation results for pollutants with the highest concentration of NOx for 1 hour,24 hours and the average of the year is 7.94;1.02;0.222(μg/m3);of CO for 1 hour and 8 hours are 27.616;8.89(μg/m3);of SO2 for 1 hour,24 hours and the average of the year is 4.005;0.288;0.038(μg/m3);of PM2.5 for 1 hour,24 hours and the average of the year is 0.32;0.023;0.003(μg/m3);of PM10 in 1 hour,24 hours and year average are 1.03;0.074;0.098(μg/m3).展开更多
In this paper potential seismic sources in coastal region of South China are identified by integration of genetic algorithm (GA) and back propagation (BP algorithm). GA is used for finding the best parameter combinati...In this paper potential seismic sources in coastal region of South China are identified by integration of genetic algorithm (GA) and back propagation (BP algorithm). GA is used for finding the best parameter combination rapidly in an infinite solution space for artificial neural networks (ANN). The results show that the distribution of potential seismic sources with different upper magnitude demarcated by this classifier is mostly satisfied the intrinsic relationship between seismic environment and earthquake occurrence, with less effect from subjective judgment of human being.展开更多
Based on the collection and analysis of achievements of other scholars, and by consulting the results of seismic safety evaluation of engineering sites and field surveys of recent years, the seismotectonic indicators ...Based on the collection and analysis of achievements of other scholars, and by consulting the results of seismic safety evaluation of engineering sites and field surveys of recent years, the seismotectonic indicators are determined for northwest Yunnan and its vicinity, and then potential seismic sources are further delineated. In practice, the following principles are applied: for areas with strong historical earthquakes, the recurrence principle is used to determine the upper bound magnitude; for areas with distinct seismogenic structure but no historical strong earthquake records, the tectonic analogy principle is used in the light of the size and activity behavior of the structure; for areas where the segmentation of the active fault is well studied, the potential sources will be demarcated more precisely; and for areas with buried fault, the seismicity pattern and geophysical abnormity are used to determine the direction of the major axis of the potential seismic source.展开更多
The characteristics of seismogenic structures are an important basis for delineating the potential seismic source areas and determining the annual occurrence rate of earthquakes. The potential seismic source area does...The characteristics of seismogenic structures are an important basis for delineating the potential seismic source areas and determining the annual occurrence rate of earthquakes. The potential seismic source area does not only have the intension that “this area has the possibility for destructive earthquakes to occur in the future" but also means that earthquakes of high magnitude interval have the characteristics of similar recurrence. When determining the seismic activity parameters of a statistical unit, some active tectonic blocks in the unit may have different background earthquakes. In order to better reflect the heterogeneity in space of seismic activities, it is necessary to divide the potential seismic source areas into three orders. By analyzing the recurrence characteristics of earthquakes of high magnitude interval in the potential source area and calculating the occurrence probability of earthquakes of high magnitude interval in the potential seismic source area in the time window for prediction, the average annual occurrence rate of earthquakes can be obtained by the method of probability equivalent conversion in the time window for prediction. This would be helpful for considering the recurrence characteristics of strong earthquakes in potential source areas within the framework of seismic risk analysis of China. Besides, the insufficient frequency of characteristic earthquakes of the next high magnitude interval in the potential source area and the heterogeneity of strong earthquakes on seismogenic structures are analyzed to see their application in seismic risk analysis.展开更多
In this paper,an approach is developed to optimize the quality of the training samples in the conventional Artificial Neural Network(ANN)by incorporating expert knowledge in the means of constructing expert-rule sampl...In this paper,an approach is developed to optimize the quality of the training samples in the conventional Artificial Neural Network(ANN)by incorporating expert knowledge in the means of constructing expert-rule samples from rules in an expert system,and through training by using these samples,an ANN based on expert-knowledge is further developed.The method is introduced into the field of quantitative identification of potential seismic sources on the basis of the rules in an expert system.Then it is applied to the quantitative identification of the potential seismic sources in Beijing and its adjacent area.The result indicates that the expert rule based on ANN method can well incorporate and represent the expert knowledge in the rules in an expert system,and the quality of the samples and the efficiency of training and the accuracy of the result are optimized.展开更多
Studying the contribution of regional transport to ultrafine particles(UFPs)and the deposition effect of nanoscale particles in human respiratory system is conducive to exploring the impact of atmospheric particles on...Studying the contribution of regional transport to ultrafine particles(UFPs)and the deposition effect of nanoscale particles in human respiratory system is conducive to exploring the impact of atmospheric particles on the environment and human health.Based on the data set of number concentration spectrum in the particle size range of 5.6–560 nm in the spring of Hefei,the Yangtze River Delta region obtained by a fast mobility particle sizer,the explosive growth characteristics,potential source identification and deposition flux analysis of UFPs were systematically studied.The results showed that the frequency of new particle formation(NPF)events during spring was 31.5%.SO_(2) and O_(3) contribute to NPF events.Daytime,higher temperature,stronger solar radiation and lower humidity were more conducive to the explosive growth of UFPs.In addition,regional transport of pollutants from the cities around Hefei played an important role in the accumulation mode particles,which were mainly affected by the land-source air mass from northwest Jiangsu(23.64%)and the sea-source air mass from the Yellow Sea(23.99%).It was worth noting that approximately 10,406 ng of UFPs enters the human respiratory system every day.Themain deposition area of 5.6–560 nm nanoscale particles was alveolar,5.6–400 nm is more likely to be deposited on alveolar,while nanoscale particles with particle size between 400 and 560 nm is more likely to be deposited on head airways.This study identified the deposition risk of nanoscale particles in the respiratory system under different particle sizes.展开更多
Ferromanganese nodules and crusts contain relatively high concentration of rare earth elements（REE） and yttrium（REY）,with a growing interest in exploitation as an alternative to land-based REY resources.On the bas...Ferromanganese nodules and crusts contain relatively high concentration of rare earth elements（REE） and yttrium（REY）,with a growing interest in exploitation as an alternative to land-based REY resources.On the basis of comprehensive geochemical approach,the abundance and distribution of REY in the ferromanganese nodules from the South China Sea are analyzed.The results indicate that the REY contents in ferromanganese deposits show a clear geographic regularity.Total REY contents range from 69.1×10^-6 to 2 919.4×10^-6,with an average value of 1 459.5×10^-6.Especially,the enrichment rate of Ce content is high,accounting for almost 60% of the total REY.This REE enrichment is controlled mainly by the sorption of ferromanganese oxides and clay minerals in the nodules and crusts.Moreover,the total REY are higher in ferromanganese deposits of hydrogenous origin than of diagenetic origin.Finally,Light REE（LREE） and heavy REE（HREE） oxides of the ferromanganese deposits in the study area can be classified into four grades： non-enriched type,weakly enriched type,enriched type,and extremely enriched type.According to the classification criteria of rare earth resources,the Xisha and Zhongsha platform-central deep basin areas show a great potential for these rare earth metals.展开更多
基金supported by the National Natural Science Foundation of China (No.42201151)the Basic Research Fund of the Chinese Academy of Meteorological Sciences (Nos.2023Z004 and 2024Z007)。
文摘Black carbon (BC) aerosols are considered key factors that contribute to rapid climate warming and ice melt in the Arctic region.However,compared with long-term observations from land-based stations,observational data over the Arctic Ocean remain relatively scarce.Four Arctic scientific expeditions were conducted in the summer and early autumn of 2010,2012,2016,and 2018 via the Chinese research vessel Xue Long,during which the BC concentrations along the routes were measured via light absorption methods.In this work,the spatiotemporal distribution characteristics of BC over the Arctic Ocean were examined on the basis of these observations.The potential sources of BC along the various routes were analyzed via the weighted potential source contribution function and weighted concentrationweighted trajectory methods of the hybrid single-particle Lagrangian integrated trajectory model in conjunction with Arctic transport potential climate model simulations.The analysis results indicated that wildfires in the western Aleutian Islands,Siberia,and Far East regions were the primary contributors to the BC aerosol concentration observed along the Arctic expedition routes in summer,identifying these regions as major potential source areas.
基金supported by the National Natural Science Foundation of China(Nos.42121004,42275107,and 42077205)the National Key Research and Development Plan(No.2023YFC3706202)+1 种基金the Foundational and Applied Basic Research in Guangzhou in 2023(No.2023A04J0251)the Special Fund Project for Science and Technology Innovation Strategy of Guangdong Province(No.2019B121205004)。
文摘This study tracked the characteristics of atmospheric wet deposition of the toxic element arsenic(As)at both urban(Guangzhou(GZ))and forested(Dinghushan Natural Reserve(DHS))sites within the Pearl River Delta(PRD)region between 2016 and 2019,examining its correlation with rainfall patterns.Additionally,by employing backward trajectory analysis and the potential source contribution function(PSCF)in conjunction with pertinent emission inventories,we pinpointed the main pathways of atmospheric arsenic transport and evaluated the emission contributions from priority source areas.The study revealed that the atmospheric arsenic wet deposition fluxes at the GZ and DHS sites exhibited a trend of increase followed by a decrease over the four-year period.Wet season deposition fluxes were more than triple those of the dry season,with urban site showing a difference of over four times.Notably,wet season As deposition at both sites was predominantly affected by heavy rainfall from marine air masses,constituting 31%of the total deposition.The predominant trajectory directions contributing to arsenic deposition at GZ and DHS were northeast(55%)and south(53%),respectively.The primary source areas for both sites were largely outside the PRD region,with the GZ site having 80%to 95%of its source area in the non-PRD region,compared to 69%to 88%at the DHS site.Furthermore,non-PRD areas contributed approximately 65%to arsenic emissions for both sites,with the industrial sector being the dominant emission source,exceeding 97%of the total emissions.
基金supported by The National Key Research and Development Program of China(No.2017YFC0209500)the National Natural Science Foundation of China(Nos.91744204,41822703,and 91844301)National research program for key issues in air pollution control(No.DQGG-0103)。
文摘A distinctive kind of organic carbon aerosol that could absorb ultraviolet-visible radiation is called brown carbon(Br C),which has an important positive influence on radiative budget and climate change.In this work,we reported the absorption properties and potential source of Br C based on a seven-wavelength aethalometer in the winter of 2018–2019 at an urban site of Sanmenxia in Fenwei Plain in central China.Specifically,the mean value of Br C absorption coefficient was 59.6±36.0 Mm^(-1) at 370 nm and contributed 37.7%to total absorption,which made a significant impact on visibility and regional environment.Absorption coefficients of Br C showed double-peak pattern,and Br C had shown small fluctuations under haze days compared with clean days.As for the sources of Br C,Br C absorption coefficients expressed strong correlations with element carbon aerosols and primary organic carbon aerosols,indicating that most of Br C originated from primary emissions.The linear correlations between trace metal elements(K,As,Fe,Mn,Zn,and Pb)and Br C absorption coefficients further referred that the major sources of Br C were primary emissions,like coal burning,biomass burning,and vehicle emissions.The moderate relationship between Br C absorption coefficients and secondary organic aerosols suggested that secondary production of Br C also played an important role.The 120 hr backward air mass trajectories analysis and concentration-weighted trajectories analysis were also used to investigate potential sources of Br C in and around this area,which inferred most parts of Br C were derived from local emissions.
基金supported by National Key Research and Development Plan(No.2017YFC0210100)the National Natural Science Foundation of China(Nos.41905086,41905107,42077205,41425020)+4 种基金the Special Fund Project for Science and Technology Innovation Strategy of Guangdong Province(No.2019B121205004)the Natural Science Foundation of Guangdong Province(No.2019A1515011291)the China Postdoctoral Science Foundation(No.2020M683174)the Air Quip(High resolution Air Quality Information for Policy)Project funded by the Research Council of Norway,the Collaborative Innovation Center of Climate Change,Jiangsu province,China,the high-performance computing platform of Jinan University,the Mt.Dinghu Forest Ecosystem Research Station,Chinese Academy of Sciences(CAS)the Comprehensive Observation and Study Site of Urban Meteorology and Environment,Sun Yat-sen University,and the Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies(No.2020B1212060025)
文摘This study attempts to identify the dominant transport pathways,potential source areas,and their seasonal variation at sites with high inorganic nitrogen(IN)wet deposition flux in southern China.This is a long-term study(2010-2017)based on continuous deposition measurements at the Guangzhou urban site(GZ)and the Dinghushan Natural Reserve site(DHS)located in the Pearl River Delta(PRD)region.A dataset on monthly IN concentration in precipitation and wet deposition flux were provided.The average annual fluxes measured at both sites(GZ:33.04±9.52,DHS:20.52±10.22 kg N/(ha·year))were higher,while the ratios of reduced to oxidized N(GZ:1.19±0.77,DHS:1.25±0.84)were lower compared with the national mean level and the previous reported level throughout the PRD region.The dominant pathways were not always consistent with the highest proportional trajectory clusters.The transport pathways contributing most of deposition were identified in the north and northnortheast in the dry season and in the east-southeast,east,and south-southwest in the wet season.A weighted potential source contribution function(WPSCF)value>0.3 was determined reasonably to define the potential source area.Emission within the PRD region contributed the majority(≥95%at both sites)of the IN deposition in the wet season,while the contribution outside the region increased significantly in the dry season(GZ:27.86%,DHS:95.26%).Our results could help create more effective policy to control precursor emissions for IN fluxes,enabling reduction of the ecological risks due to excessive nitrogen.
基金supported by the Major Program of Science and Technology of Hainan Province,China(No.ZDKJ202007)the Special Foundation of Government Financial of Hainan Province,China(No.ZC2018-196)the Youth Innovation Foundation of Hainan Research Academy of Environmental Sciences,China(No.QNCX2021002)。
文摘Based on one-year observation,the concentration,sources,and potential source areas of volatile organic compounds(VOCs)were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haikou,China.The results showed that the annual average concentration of total VOCs(TVOCs)was 11.4 ppb V,and the composition was dominated by alkanes(8.2 ppb V,71.4%)and alkenes(1.3 ppb V,20.5%).The diurnal variation in the concentration of dominant VOC species showed a distinct bimodal distribution with peaks in the morning and evening.The greatest contribution to ozone formation potential(OFP)was made by alkenes(51.6%),followed by alkanes(27.2%).The concentrations of VOCs and nitrogen dioxide(NO_(2))in spring and summer were low,and it was difficult to generate high ozone(O_(3))concentrations through photochemical reactions.The significant increase in O_(3)concentrations in autumn and winter was mainly related to the transmission of pollutants from the northeast.Traffic sources(40.1%),industrial sources(19.4%),combustion sources(18.6%),solvent usage sources(15.5%)and plant sources(6.4%)were identified as major sources of VOCs through the positive matrix factorization(PMF)model.The southeastern coastal areas of China were identified as major potential source areas of VOCs through the potential source contribution function(PSCF)and concentration-weighted trajectory(CWT)models.Overall,the concentration of ambient VOCs in Haikou was strongly influenced by traffic sources and long-distance transport,and the control of VOCs emitted from vehicles should be strengthened to reduce the active species of ambient VOCs in Haikou,thereby reducing the generation of O_(3).
基金supported by the National Natural Science Foundation of China(No.41775029)the National Key Research and Development Project of China(No.2018YFC0213201)the Science and Technology Commission of Shanghai Municipality(No.17DZ1203102).
文摘Long-term stereoscopic observations of aerosol,NO2,and HCHO were carried out at the Yangmeikeng(YMK)site in Shenzhen.Aerosol optical depths and NO2 vertical column concentration(NO2 VCD)derived from MAX-DOAS were found to be consistent with other datasets.The total NO2 VCD values of the site remained low,varying from 2×10^(15)to 8×10^(15)mol/cm^(2),while the HCHO VCD was higher than NO2 VCD,varying from 7×10^(15)to 11×10^(15)mol/cm^(2).HCHO VCD was higher from September to early November than that was from mid-late November to December and during February 2021,in contrast,NO2 VCD did not change much during the same period.In January,NO2 VCD and HCHO VCD were both fluctuating drastically.High temperature and HCHO level in the YMK site is not only driving the ozone production up but alsomay be driving up the ozone concentration as well,and the O_(3)production regime in the YMK site tends to be NOx-limited.At various altitudes,backward trajectory clustering analysis and Potential Source Contribution Function(PSCF)were utilized to identify possible NO2 and HCHO source locations.The results suggested that the Huizhou-Shanwei border and the Daya Bay Sea area were the key potential source locations in the lower(200 m)and middle(500 m)atmosphere(WPSCF>0.6).The WPSCF valuewas high at the 1000maltitude whichwas closer to the YMKsite than the near ground,indicating that the pollution transport capability in the upper atmosphere was limited.
基金The research was supported by the key project entitled"Seismic Safety Evaluation and Seismic Structure Study"under the 10th Five-Year Plan of China EarthquakeAdministration
文摘Based on the results of focal mechanism solutions in southeastern areas of China （south of 34°N and east of 105° E）, this article analyzes the correlation of focal mechanism solutions with seismogenic structures of moderate strong earthquakes and the direction of potential source zones. The data show that the nodal planes of focal mechanism solutions and the principle stresses in southern China are of predominantly similar directions, most of the solutions for M ≥4.0 earthquakes correspond to the main structure directions as well as the directions of potential source zones. The statistical results of multiple small earthquakes concerning nodal planes and main stress axes are also reliable for determining the direction of potential source zones. According to the analysis of focal mechanism solutions, long-axis direction of isoseismals distribution of aftershocks, geologic structures, and seismic activity in two areas of the Ms6.1 earthquake in the south Yellow Sea in 1996 and the MsS.2 earthquake in Fujian in 1997, the potential source zone division is discussed.
基金supported by the Ministry of Science and Technology of China(Nos.2021YFC3200904 and 2022YFC3203705)the National Natural Science Foundation of China(Nos.52270012 and 52070184).
文摘Phthalate esters(PAEs),recognized as endocrine disruptors,are released into the environment during usage,thereby exerting adverse ecological effects.This study investigates the occurrence,sources,and risk assessment of PAEs in surface water obtained from 36 sampling points within the Yellow River and Yangtze River basins.The total concentration of PAEs in the Yellow River spans from124.5 to 836.5 ng/L,with Dimethyl phthalate(DMP)(75.4±102.7 ng/L)and Diisobutyl phthalate(DiBP)(263.4±103.1 ng/L)emerging as the predominant types.Concentrations exhibit a pattern of upstream(512.9±202.1 ng/L)>midstream(344.5±135.3 ng/L)>downstream(177.8±46.7 ng/L).In the Yangtze River,the total concentration ranges from 81.9 to 441.6 ng/L,with DMP(46.1±23.4 ng/L),Diethyl phthalate(DEP)(93.3±45.2 ng/L),and DiBP(174.2±67.6 ng/L)as the primary components.Concentration levels follow a midstream(324.8±107.3 ng/L)>upstream(200.8±51.8 ng/L)>downstream(165.8±71.6 ng/L)pattern.Attention should be directed towards the moderate ecological risks of DiBP in the upstream of HH,and both the upstream and midstream of CJ need consideration for the moderate ecological risks associated with Di-n-octyl phthalate(DNOP).Conversely,in other regions,the associated risk with PAEs is either low or negligible.The main source of PAEs in Yellow River is attributed to the release of construction land,while in the Yangtze River Basin,it stems from the accumulation of pollutants in lakes and forests discharged into the river.These findings are instrumental for pinpointing sources of PAEs pollution and formulating control strategies in the Yellow and Yangtze Rivers,providing valuable insights for global PAEs research in other major rivers.
基金supported by the National Natural Science Foundation of China(Nos.U23A2016,U1704241,and 42007175).
文摘Water-soluble organic nitrogen(WSON)affects the formation,hygroscopicity,acidity of organic aerosols,and nitrogen biogeochemical cycles.However,qualitative and quantitative characterizations of WSON remain limited due to its chemical complexity.In the study,1-year field samples of particulate matter 2.5(PM_(2.5))were collected fromJune 2022 to May 2023 to analyze the WSON concentration in PM_(2.5),and correlation analysis,positive matrix factor(PMF),and potential source contribution function(PSCF)modelswere employed to elucidate WSON source apportionment and transport pathways.The results revealed that the mean WSON concentrations reached 1.98±2.64μg/m^(3) with a mean WSON to water-soluble total nitrogen(WSTN)ratio of 21%.Further,WSON concentration exhibited a seasonal variation trend,with higher values in winter and lower in summer.Five sources were identified as contributors to WSON in PM_(2.5) within the reservoir area through a comprehensive analysis including correlation analysis,PSCF and concentration weighted trajectory(CWT),and PMF analyses.These sources were agricultural,dust,combustion,traffic,and industrial sources,of which agricultural source emerged as the primary contributor(76.69%).The atmosphere in the reservoir area were primarily influenced by the transport of northeastern air masses,local agricultural activities,industrial cities along the trajectory,and coastal regions,exerting significant influences on the concentration of WSON in the reservoir area.The findings of this study addressed the research gap concerning organic nitrogen in PM_(2.5) within the reservoir area,thereby offering a theoretical foundation and data support in controlling nitrogen pollution in the Danjiangkou Reservoir area.
基金supported by the National Key Research and Development Program of China(No.2022YFC3701204)the Natural Science Foundation of Jiangsu Province(No.BK20231300).
文摘Based on the chemical composition data of a regional long-lasting haze event that occurred in the Yangtze River Delta(YRD)region from 17 December 2023 to 8 January 2024,the evolutionary characteristics of the chemical components and sources of fine particulate matter(PM2.5)under different pollution levels were comparatively analyzed using PMF(Positive Matrix Factorization)and backward trajectory analysis.SNA(NO_(3)^(-),NH_(4)^(+),SO_(4)^(2-))was found to be the primary chemical component of PM2.5,making up 63.6%(clean days)to 69.7%(heavy pollution)of it.The NO_(3)^(-)concentration was 3.14(clean days)to 6.01(heavy pollution)times higher than that of SO_(4)^(2-).NO_(3)^(-),POC,Fe,Mn,Al concentrations increased,while SOC,EC,crustal elements(Ca,Si)and other water-soluble ions(WSIs)concentrations decreased as the pollution level increased.The contribution of secondary inorganics and biomass-burning emissions and industrial and ship emissions increased significantly as the pollution level increased,which accounted for 40.3%and 36.7%,respectively,in the heavy pollution stage.The contribution of traffic sources decreases gradually with increasing pollution levels,accounting for only 59.1%of the light pollution stage in the heavy pollution stage.PM_(2.5) and its main chemical components showed similar potential source distribution,located in the northwest(Fuyang,Huainan,Nanjing),south(Taizhou,Lishui,Jiande)and north(Taizhou,Yancheng).However,distinct transport routes were observed under the different air quality levels.During the heavy pollution period,the polluted air masses primarily came from the harbor regions,whereas during the light pollution period they were transported from the southeast(Taizhou)and the North China Plain.
基金supported by the National Natural Science Foundation of China(42161007)the Innovation Foundation of Higher Education Institutions of Gansu Province(2021B-081)the Foundation for Distinguished Young Scholars of Gansu Province(20JR10RA112).
文摘Precipitation isotopes(δ^(18)O and δ^(2)H)are closely related to meteorological conditions for precipitation generation and the initial state of water vapor source areas,and are essential to the study of the regional hydrological cycle.The deuterium excess(d-excess)indicates deviation in isotope fractionation during evaporation and can trace water vapor sources.This study analyzed 443 precipitation samples collected from the Gannan Plateau,China in 2022 to assess precipitation isotope variations and their driving factors.Water vapor sources were evaluated using the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT),Concentration Weighted Trajectory(CWT),and Potential Source Contribution Factor(PSCF)models.Results showed that precipitation isotope values showed significant spatial and temporal variations on the Gannan Plateau.Temporally,precipitation isotope values peaked in June(when evaporation dominated)and minimized in March(depletion effect of air masses in the westerly wind belt).Spatially,the isotope values showed a distribution pattern of"high in the east and low in the west",which was mainly regulated by the differences in altitude and local meteorological conditions.Compared with the global meteoric water line(GMWL)with equation of δ^(2)H=8.00δ^(18)O+10.00,the slope and intercept of local meteoric water line(LMWL)for precipitation on the Gannan Plateau were smaller(7.49 and 7.63,respectively),reflecting the existence of a stronger secondary evaporation effect under the clouds in the region.The sources of water vapor on the Gannan Plateau showed significant seasonality and spatial heterogeneity.Specifically,the westerly belt and monsoon were the main water vapor transport paths at each sampling point,with Central Asian continental water vapor dominating in spring(53.49%),Indian Ocean water vapor dominating in summer(52.53%),Atlantic Ocean water vapor dominating in autumn(46.74%),and Atlantic Ocean and Mediterranean Sea water vapor dominating in winter(42.30%and 33.68%,respectively).Changes in the intensity of convective activity and Outgoing Longwave Radiation(OLR)affected the enrichment of isotopic values,which exhibited the same change trends as δ^(18)O.During the precipitation process,the δ^(18)O value first decreased and then increased.During the initial and final stages of precipitation process,precipitation was mainly influenced by continental air masses,while during the middle stage,it was controlled by marine air masses.The systematic research on precipitation isotopes and water vapor sources is important for climate change research and extreme precipitation prediction on the Gannan Plateau and other similar areas.
文摘Magnitude and distance of major potential source are needed in order to determine duration time of artificial ground motion and to determine the type of response spectrum (near field or far field) when using the seismic intensity zonation map. The magnitude probabilistic distribution function of seismic belt and the magnitude and space joint distribution function for given intensity of the site in a potential Source are provided. Then the basicformula of calculating expected magnitude and expected distance are developed. Several examples for calculating expected magnitude and expected distance in northern China are discussed. These results show that expected magnitude and expected distance are related not only to geometry of potential source and magnitude but also to the intensity of the site with certain exceeding probability.
基金Joint Seismological Science Foundation of China (103051).
文摘In the paper, we have discovered the abnormal area distribution features of maximum variation values of ground motion parameter uncertainty with different probabilities of exceedance in 50 years within the range of 100°-120°E, 29°-42°N for the purpose to solve the problem that abnormal areas of maximum variation values of ground motion parameter uncertainties emerge in a certain cities and towns caused by seismicity parameter uncertainty in a seismic statistical region in an inhomogeneous distribution model that considers tempo-spatial nonuniformity of seismic activity. And we have also approached the interrelation between the risk estimation uncertainty of a site caused by seismicity parameter uncertainty in a seismic statistical region and the delimitation of potential sources, as well as the reasons for forming abnormal areas. The results from the research indicate that the seismicity parameter uncertainty has unequal influence on the uncertainty of risk estimation at each site in a statistical region in the inhomogeneous distribution model, which relates to the scheme for delimiting potential sources. Abnormal areas of maximum variation values of ground motion parameter uncertainty often emerge in the potential sources of Mu greater than or equal 8 (Mu is upper limit of a potential source) and their vicinity. However, this kind of influence is equal in the homogeneous distribution model. The uncertainty of risk estimation of each site depends on its seat. Generally speaking, the sites located in the middle part of a statistical region are only related to the seismicity parameter uncertainty of the region, while the sites situated in or near the juncture of two or three statistical regions might be subject to the synthetic influences of seismicity parameter uncertainties of several statistical regions.
基金The authors would like to thank the Ministry of Natural Resources and Environment for funding this study through the project code TNMT.2020.04.10 and Contract No.28/HD-VP signed on October 1,2020.
文摘The Northern Key Economic region of Vietnam is a dynamic economic center that is an important economic locomotive of the North and the whole of Vietnam.In this area,large industrial parks are concentrated,attracting many large FDI projects.Key industries:cement production,cars-motorcycles,electronics,...Economic development entails environmental problems.The industrial sector has been identified as the number one driving force driving the growth of Hanoi city and neighboring provinces.Therefore,industrial development is one of the main causes of environmental pollution.In addition,the growth rate of industry in neighboring provinces significantly affects the air quality in Hanoi city.Some factories in Vinh Phuc,Hung Yen,Bac Ninh and Hai Duong provinces have large sources of gas emissions,potentially affecting air quality around Hanoi city.Monitoring results show that air pollution in Hanoi city is mainly caused by dust pollution,especially PM2.5 superfine dust.This is a very harmful dust to health;it is necessary to determine the cause and control solution.Therefore,the objectives of this study are:(1)inventory of potential emissions sources for industrial activities in the northern key economic region around Hanoi;(2)Simulate air spread by AERMOD model to get an overall picture of the industrial impact of surrounding provinces in Hanoi city;(3)Propose solutions to manage air quality for the city in the coming time.Simulation results for pollutants with the highest concentration of NOx for 1 hour,24 hours and the average of the year is 7.94;1.02;0.222(μg/m3);of CO for 1 hour and 8 hours are 27.616;8.89(μg/m3);of SO2 for 1 hour,24 hours and the average of the year is 4.005;0.288;0.038(μg/m3);of PM2.5 for 1 hour,24 hours and the average of the year is 0.32;0.023;0.003(μg/m3);of PM10 in 1 hour,24 hours and year average are 1.03;0.074;0.098(μg/m3).
文摘In this paper potential seismic sources in coastal region of South China are identified by integration of genetic algorithm (GA) and back propagation (BP algorithm). GA is used for finding the best parameter combination rapidly in an infinite solution space for artificial neural networks (ANN). The results show that the distribution of potential seismic sources with different upper magnitude demarcated by this classifier is mostly satisfied the intrinsic relationship between seismic environment and earthquake occurrence, with less effect from subjective judgment of human being.
文摘Based on the collection and analysis of achievements of other scholars, and by consulting the results of seismic safety evaluation of engineering sites and field surveys of recent years, the seismotectonic indicators are determined for northwest Yunnan and its vicinity, and then potential seismic sources are further delineated. In practice, the following principles are applied: for areas with strong historical earthquakes, the recurrence principle is used to determine the upper bound magnitude; for areas with distinct seismogenic structure but no historical strong earthquake records, the tectonic analogy principle is used in the light of the size and activity behavior of the structure; for areas where the segmentation of the active fault is well studied, the potential sources will be demarcated more precisely; and for areas with buried fault, the seismicity pattern and geophysical abnormity are used to determine the direction of the major axis of the potential seismic source.
文摘The characteristics of seismogenic structures are an important basis for delineating the potential seismic source areas and determining the annual occurrence rate of earthquakes. The potential seismic source area does not only have the intension that “this area has the possibility for destructive earthquakes to occur in the future" but also means that earthquakes of high magnitude interval have the characteristics of similar recurrence. When determining the seismic activity parameters of a statistical unit, some active tectonic blocks in the unit may have different background earthquakes. In order to better reflect the heterogeneity in space of seismic activities, it is necessary to divide the potential seismic source areas into three orders. By analyzing the recurrence characteristics of earthquakes of high magnitude interval in the potential source area and calculating the occurrence probability of earthquakes of high magnitude interval in the potential seismic source area in the time window for prediction, the average annual occurrence rate of earthquakes can be obtained by the method of probability equivalent conversion in the time window for prediction. This would be helpful for considering the recurrence characteristics of strong earthquakes in potential source areas within the framework of seismic risk analysis of China. Besides, the insufficient frequency of characteristic earthquakes of the next high magnitude interval in the potential source area and the heterogeneity of strong earthquakes on seismogenic structures are analyzed to see their application in seismic risk analysis.
文摘In this paper,an approach is developed to optimize the quality of the training samples in the conventional Artificial Neural Network(ANN)by incorporating expert knowledge in the means of constructing expert-rule samples from rules in an expert system,and through training by using these samples,an ANN based on expert-knowledge is further developed.The method is introduced into the field of quantitative identification of potential seismic sources on the basis of the rules in an expert system.Then it is applied to the quantitative identification of the potential seismic sources in Beijing and its adjacent area.The result indicates that the expert rule based on ANN method can well incorporate and represent the expert knowledge in the rules in an expert system,and the quality of the samples and the efficiency of training and the accuracy of the result are optimized.
基金supported by the National Natural Science Foundation of China(Nos.U21A2027,42207113,and 42407141)。
文摘Studying the contribution of regional transport to ultrafine particles(UFPs)and the deposition effect of nanoscale particles in human respiratory system is conducive to exploring the impact of atmospheric particles on the environment and human health.Based on the data set of number concentration spectrum in the particle size range of 5.6–560 nm in the spring of Hefei,the Yangtze River Delta region obtained by a fast mobility particle sizer,the explosive growth characteristics,potential source identification and deposition flux analysis of UFPs were systematically studied.The results showed that the frequency of new particle formation(NPF)events during spring was 31.5%.SO_(2) and O_(3) contribute to NPF events.Daytime,higher temperature,stronger solar radiation and lower humidity were more conducive to the explosive growth of UFPs.In addition,regional transport of pollutants from the cities around Hefei played an important role in the accumulation mode particles,which were mainly affected by the land-source air mass from northwest Jiangsu(23.64%)and the sea-source air mass from the Yellow Sea(23.99%).It was worth noting that approximately 10,406 ng of UFPs enters the human respiratory system every day.Themain deposition area of 5.6–560 nm nanoscale particles was alveolar,5.6–400 nm is more likely to be deposited on alveolar,while nanoscale particles with particle size between 400 and 560 nm is more likely to be deposited on head airways.This study identified the deposition risk of nanoscale particles in the respiratory system under different particle sizes.
基金The National Natural Science Foundation of China under contract Nos 41376057,41306047,41676056the Spanish project SUBVENT under contract No.CGL2012-39524-C02
文摘Ferromanganese nodules and crusts contain relatively high concentration of rare earth elements（REE） and yttrium（REY）,with a growing interest in exploitation as an alternative to land-based REY resources.On the basis of comprehensive geochemical approach,the abundance and distribution of REY in the ferromanganese nodules from the South China Sea are analyzed.The results indicate that the REY contents in ferromanganese deposits show a clear geographic regularity.Total REY contents range from 69.1×10^-6 to 2 919.4×10^-6,with an average value of 1 459.5×10^-6.Especially,the enrichment rate of Ce content is high,accounting for almost 60% of the total REY.This REE enrichment is controlled mainly by the sorption of ferromanganese oxides and clay minerals in the nodules and crusts.Moreover,the total REY are higher in ferromanganese deposits of hydrogenous origin than of diagenetic origin.Finally,Light REE（LREE） and heavy REE（HREE） oxides of the ferromanganese deposits in the study area can be classified into four grades： non-enriched type,weakly enriched type,enriched type,and extremely enriched type.According to the classification criteria of rare earth resources,the Xisha and Zhongsha platform-central deep basin areas show a great potential for these rare earth metals.
