Study on the Total Amount Control of Atmospheric Pollutant Based on GIS

To provide effective environmental management for total amount control of atmospheric pollutants. Methods An atmospheric diffusion model of sulfur dioxide on the surface of the earth was established and tested in Shantou of Guangdong Province on the basis of an overall assessment of regional natural environment, social economic state of development, pollution sources and atmospheric environmental quality. Compared with actual monitoring results in a studied region, simulation values fell within the range of two times of error and were evenly distributed in the two sides of the monitored values. Predicted with the largest emission model method, the largest emission of sulfur dioxide would be 54 279.792 tons per year in 2010. Conclusion The mathematical model established and revised on the basis of GIS is more rational and suitable for the regional characteristics of total amount control of air pollutants.

Discussion on Atmospheric Pollutant Source Seeking Model with Surface Soil Sample

Through the analysis on the migratory diffusion process of atmospheric pollutants,we proposed to seek atmospheric pollutant source with surface soil sample of data.Based on Gaussian plume model and deposition model,atmospheric pollutants distribution model was deduced,with which a schema matching source seeking model was established.The model was used to seek the pollutant source by using the arsenic data in the surface soil sample of a city.

Case Study of Atmospheric Pollutant Diffusion Data Based on Gaussian Model

Air pollution as one of the major environmental issues in modern society,has already brought severe impact to human life and production,thus it is an urgent task for studying environmental and ecological science to solve this issue that has bothered human society for the last centuries.Scientists have endeavored to figure out the laws of atmospheric pollutant diffusion using various mathematical models and statistical models,and drawn some precious conclusions.This paper explored the basic model of atmospheric diffusion—modeling and solution of Gaussian Diffusion Model,clarify its principles and operation forms,then applied the model into the PM_(2.5) atmospheric diffusion cases,make the program planning base on the results of model calculation,and get the final conclusion.

Impact of Concentration Levels of Atmospheric Pollutants on Local Climate of Delta State, Nigeria

Studies in various regions of the world have revealed that air pollution can have a significant influence on local climate. This study therefore considers the impact of concentration levels of atmospheric pollutants on local climate of Delta state, Nigeria. Monthly and annual averaging of the daily pollutant concentrations and meteorological parameters within the period of investigation was carried out. Descriptive Statistics, correlation analysis, coefficient of determination (R2) analysis and least squares regression analysis of the selected meteorological parameters with CH4 and O3 concentrations for the period of 2003 to 2012 and NO2 and CO2 concentrations for the period of 2011 to 2014 were carried out. The regression relationship was then used to obtain predicted values for the meteorological parameters within the period of investigation. The results of the descriptive statistics of annual averages of CH4, O3, NO2 and CO2 concentrations within the period of investigation revealed that the emission levels breached FEPA and EGASPIN limits. The results of the correlation analysis indicated that CO2 had a strong significant positive correlation with temperature with a correlation coefficient of 0.962, while a moderate negative correlation coefficient of 0.549 was obtained for CH4, and very weak correlation coefficients of -0.167 and 0.077 were obtained for O3 and NO2 respectively. CH4, O3 and CO2 had a moderately significant positive correlation with solar radiation with correlation coefficients of 0.661, 0.571 and 0.656 respectively, while a weak negative correlation coefficient of 0.106 was obtained for NO2. CH4 had a strong significant positive correlation with relative humidity with a correlation coefficient of 0.859, while moderate correlation coefficients of -0.516 and 0.646 were obtained for NO2 and CO2 respectively, and a weak correlation coefficient of 0.345 was obtained for O3. CO2 and CH4 had a strong significant correlation with wind speed with correlation coefficients of 0.951 and -0.906 respectively, while a moderate negative correlation coefficient of 0.518 was obtained for O3, and a weak negative correlation coefficient of 0.317 was obtained for NO2. The predicted values of the meteorological parameters showed a significant level of agreement with their measured values. Therefore, among the atmospheric pollutants postulated as influencing meteorological parameters, CO2 appears to be the most strongly significant in explaining temperature variations in this region of Niger Delta, with correlation coefficient of 96.2% and coefficient of determination (R2) of 0.926, implying that CO2 influenced 92.6% variation in temperature in this part of Niger Delta within the period of investigation.

Analysis of Concentration Levels of Atmospheric Pollutants in Warri, Nigeria

A critical environmental problem facing the Niger Delta region is Air Pollution. This study therefore analyses concentration levels of atmospheric pollutants in the region. Statistical analysis of CH4 and O3 concentrations for the period of 2003 to 2012 and NO2 and CO2 concentrations for the period of 2011 to 2014 were carried out. The results showed that concentration levels of the pollutants were lower during the rainy season than during the dry year time. This is due to higher occurrences of atmospheric instability during the rainy season. On the other hand, ozone (O3) concentration reached its peak value during the peak period of the rainy season unlike the other pollutants. In all likelihood, some of the ozone-depleting substances such as aerosols and atmospheric hydrogen chloride become soluble in water and are being washed off by precipitation during rainy season, thereby leading to increased tropospheric ozone concentration during the rainy season. The study also revealed a steady increase in the concentration of CO2 within the period of investigation. This steady increase in CO2 can be traced to the alarming increase in anthropogenic activities which appreciably increases the amount of CO2 in the atmosphere. Methane (CH4) had higher standard deviation values than carbon dioxide (CO2), meaning that on a per molecule basis, a proportional rise in CH4 is much more effective as a greenhouse gas than a similar increase in CO2. However, CO2 has a greater effect than CH4 on climate change owing to its higher atmospheric concentration. The Mann-Kendall rank statistics of the atmospheric pollutants revealed that the standardization variables U(ti) and U'(ti) have a sequential fluctuating behavior around a zero level.

Advances in catalytic elimination of atmospheric pollutants by two-dimensional transition metal oxides

Atmospheric pollutants can deteriorate air quality and put human health at risk.There is a growing need for green,economical,and efficient technologies,among which catalytic elimination technology is the most promising,to remove atmospheric pollutants.Two-dimensional transition metal oxides(2D TMOs)have recently become attractive catalysts due to their highly exposed active sites,excellent reactant transport properties,and extraordinary catalytic performance.This review systematically summarizes the topdown and bottom-up preparation methods of 2D TMOs and focuses on the specific applications of 2D TMOs in the catalytic elimination of atmospheric inorganic pollutants and volatile organic pollutants.The development of 2D TMOs in the catalytic elimination of atmospheric pollutants is prospected.This review is expected to provide design insights into efficient 2D TMOs to remove atmospheric pollutants.

A new prediction method of industrial atmospheric pollutant emission intensity based on pollutant emission standard quantification

Industrial emissions are the main source of atmospheric pollutants in China.Accurate and reasonable prediction of the emission of atmospheric pollutants from single enterprise can determine the exact source of atmospheric pollutants and control atmospheric pollution precisely.Based on China’s coking enterprises in 2020,we proposed a quantitative method for pollutant emission standards and introduced the quantification results of pollutant emission standards(QRPES)into the construction of support vector regression(SVR)and random forest regression(RFR)prediction methods for SO_(2) emission of coking enterprises in China.The results show that,affected by the types of coke ovens and regions,China’s current coking enterprises have implemented a total of 21 emission standards,with marked differences.After adding QRPES,it was found that the root mean squared error(RMSE)of SVR and RFR decreased from 0.055 kt/a and 0.059 kt/a to 0.045 kt/a and 0.039 kt/a,and the R2 increased from 0.890 and 0.881 to 0.926 and 0.945,respectively.This shows that the QRPES can greatly improve the prediction accuracy,and the SO_(2) emissions of each enterprise are highly correlated with the strictness of standards.The predicted result shows that 45%of SO_(2) emissions from Chinese coking enterprises are concentrated in Shanxi,Shaanxi and Hebei provinces in central China.The method created in this paper fills in the blank of forecasting method of air pollutant emission intensity of single enterprise and is of great help to the accurate control of air pollutants.

Distribution of Atmospheric Pollution in Southern Benin

This study focuses on air quality in southern Benin in order to show public authorities what the Beninese populations are exposed to for efficient decision-making. Two sampling campaigns were carried out, one in the wet period and the other in the dry season. The measurements were taken using a monitor called an “Air Quality Monitor”. For data processing, the multiple comparison methods of Dun (1961) and the Wilcoxon test were used. To maintain legitimacy, all spatial data were included in the official cartographic repository of Benin: WGS 1984, Transverse Mercator Universe Projection (UTM), Zone 31 North. The Moran statistic was used to measure the levels of spatial autocorrelation of the variables studied and to test the significance. In order to locate the spatial subsets, the local spatial association indices of Anselin Local Moran and Getis-Ord, Gi* were used. In terms of results, on the 13 monitoring sites and the 8 parameters chosen to determine air quality, we do not note any significant inter-seasonal difference. Of the eight parameters, only three parameters present spatial autocorrelation leading to predictions of ambient air quality over the entire study area based on the distance separating the points, namely, PM2.5, PM10 and ambient air quality index (AQI). The localities affected by atmospheric pollution in South Benin are located in the south-western part of Benin, headed by Cotonou, which is heavily polluted by CO2, TCOV, PM10 and PM2.5.

Observations of atmospheric pollutants at Lhasa during 2014-2015:Pollution status and the influence of meteorological factors

Atmospheric pollutants including SO_2, NO_2, CO, O_3 and inhalable particulate matter（PM2.5 and PM10） were monitored continuously from March 2014 to February 2015 to investigate characteristics of air pollution at Lhasa, Tibetan Plateau. Species exhibited similar seasonal variations except O_3, with the peaks in winter but low valleys in summer. The maximum O_3 concentration was observed in spring, followed by summer, autumn, and winter. The positive correlation between O_3 and PM10 in spring indicated similar sources of them, and was assumed to be turbulent transport. Temperature was the dominant meteorological factor for most species in spring. High temperature accelerates O_3 photochemistry, and favors air disturbance which is conductive to dust resuspension in spring. Relative humidity（RH） and atmospheric pressure were the main meteorological factors in summer. RH showed negative correlations with species, while atmospheric pressure posed opposite situation. Wind speed（WS） was the dominant meteorological factor in autumn, the negative correlations between WS and species indicated diffusion by wind. Most species showed non-significant correlations with meteorological factors in winter, indicating the dependence of pollution on source emission rather than restriction by meteorology. Pollution weather character indicated that emissions were from biomass burning and dust suspension, and meteorological factors also played an important role. Air stream injection from the stratosphere was observed during O_3 pollution period. Air parcels from Southwest Asia were observed during air pollution period in winter. An enhancement in air pollutants such as O_3 would be expected in the future, more attention should be given to countermeasures for prevention of air pollution in the future.

Ten-year emission characteristics of atmospheric pollutants from incineration of sacrificial offerings in China

The incineration of sacrificial offerings is a significant widely practiced custom that is also a kind of neglected air pollution source in China.Our results showed that the emission factors of particulate matter,SO_(2),CO,NO_(x),and VOCs emitted from the incineration of sacrificial offerings with purification systems were reduced by 95%,19%,9%,82%,and 42%,respectively,compared with those without a purification system,revealing a significant effect of the flue gas purification system on reducing particulate matter and gaseous pollutants.The emission level of air pollutants from the incineration of sacrificial offerings remained stable before 2013 and then showed a remarkable decrease after the implementation of China′s Air Pollution Prevention Action Plan in 2013.The emissions of TSP(total suspended particulate),PM_(10),PM_(2.5),and NO_(x)in 2009 were 8222,6106,5656 and 15,878 ton,respectively,obviously higher than 3434,2551,2305 and 8579 ton in 2019.Such trend was affected by both the quantity of incineration and the installation rate of purification systems after the Emission Standard of Air Pollutants for Crematory(GB 13801-2015)issued in China.Distinct spatial distribution of atmospheric pollutants from incineration of sacrificial offerings was found with higher in the east and south of China than the west and north of China,which is proportional to the regional economy and population.The maximum ground-level concentration typically occurred at 0.12-0.2 km from the pollution source,posing potential health risks to people entering and exiting funeral and burial sites and nearby residents.

Comprehensive and high-resolution emission inventory of atmospheric pollutants for the northernmost cities agglomeration of Harbin-Changchun,China:Implications for local atmospheric environment management

Using a bottom-up estimation method,a comprehensive,high-resolution emission inventory of gaseous and particulate atmospheric pollutants for multiple anthropogenic sectors with typical local sources has been developed for the Harbin-Changchun city agglomeration(HCA).The annual emissions for CO,NO_(x),SO_(2),NH_(3),VOC S,PM_(2.5),PM 10,BC and OC during 2017 in the HCA were estimated to be 5.82 Tg,0.70 Tg,0.34 Tg,0.75 Tg,0.81 Tg,0.67 Tg,1.59 Tg,0.12 Tg and 0.26 Tg,respectively.For PM 10 and SO_(2),the emissions from industry processes were the dominant contributors representing 54.7%and 49.5%,respectively,of the total emissions,while 95.3%and 44.5%of the total NH_(3)and NO x emissions,respectively,were from or associated with agricultural activities and transportation.Spatiotemporal distributions showed that most emissions(except NH_(3))occurred in November to March and were concentrated in the central cities of Changchun and Harbin and the surrounding cities.Open burning of straw made an important contribution to PM_(2.5)in the central regions of the northeastern plain during autumn and spring,while domestic coal combustion for heating purposes was significant with respect to SO_(2)and PM_(2.5)emissions during autumn and winter.Furthermore,based on Principal Component Analysis and Multivariable Linear Regression model,air temperature,relative humidity,electricity and energy consumption,and the urban and rural population were optimized to be representative indicators for rapidly assessing the magnitude of regional atmospheric pollutants in the HCA.Such indicators and equations were demonstrated to be useful for local atmospheric environment management.

Feature Analysis of the Atmospheric Particulate Pollutants (PM_(10) and PM_(2.5)) in Wenzhou City

[ Objective] The research aimed to analyze characteristics of the atmospheric particulate pollutants （ PMlo and PM2.s） in Wenzhou City. [Method] We analyzed interannual change rule of the dust haze in Wenzhou during 1978 -2008. Moreover, we respectively set monitoring points in urban district, industrial park and beauty spot of Wenzhou in summer and winter of 2010. Element, ion and polycyclic aromatic hydrocarbon com- positions and morphology of the particulate matter were analyzed. [ Result] Dust haze in Wenzhou City mainly appeared in winter and spring, which was related to local meteorological condition. In summer and winter, both PMlo and PM2.s concentrations presented the characteristic of industrial park 〉 commercial area 〉 beauty spot. Chain-like particle aggregates and ultrafine particles were main composition of the atmospheric particulate matter in Wenzhou. Contribution rate of the spherical particle amount was smaller than metropolis, which was related to local industry and traffic. Fe element had the most content in particulate matter. Mass concentration was mainly composed of 6 elements, such as Na, Si, S, K, Ca and Fe. Total concentration of the six elements occupied 70% -80% of the 16 elements. SO^- and NH4＊ in particulate matter were higher. They were mainly from human activity. Main compositions of the polycyclic aromatic hydrocarbon were naphthalene, anthracene, benzo （b） fluoranthene, indeno （1,2, 3-cd） pyrene and benzo （g, h, i） perylene, which was related to abrupt increase of the motor vehicle. [ Condusion] The research provided scientific basis and technology support for controlling atmospheric particulate matter pollution in Wenzhou City by government and related department.

Level of Exposure of Populations to Atmospheric Pollution in Southern Benin

This study focuses on monitoring the exposure of populations in South Benin to atmospheric pollution. Thirteen (13) monitoring points were identified where the Air quality measurements were taken using autonomous electronic devices called “Air Quality Monitor”. Calibrated and turned on, the measuring device automatically determines the concentrations of carbon dioxide CO2, Total Organic Compounds, methanal (HCHO), particulate matter PM2.5 and PM10, temperature in degrees Fahrenheit and relative humidity (RH). Per site, air pollution levels are recorded for 5 minutes every 30 minutes from 7 a.m. to 6 p.m. After the analyses, it appears that the carbon dioxide CO2 contents vary from 400 to 1444 ppm with an average of 486.80 ± 184.3 ppm, the daily contents of Total Volatile Organic Compounds from 0.01 to 6 .91 mg/m3 with a daily average of 0.36 ± 0.65 mg/m3, aldehydes from 0.005 to 3 mg/m3 with an average of 0.05 ± 0.17 mg/m3, for particulate matter of diameters less than or equal to 2.5 μm (PM2.5) pollution levels vary between 5 and 173.8 μg/m3 with an average of 21.5 ± 17.62 μg/m3. On the other hand, for PM10, the contents vary from 5 to 449.6 μg/m3 with an average of 28.17 ± 31.74 μg/m3, the Air Quality Index (AQI) varies from 0, 3 to 243 with an average of 39 ± 33.16. From the results observed, it appears that the south-western part of South Benin is heavily polluted by CO2, Total Volatile Organic Compounds, PM10 and especially PM2.5 with the city of Cotonou at its head, in particular the Red Star crossroads, the Toyota crossroads and the crossroads after the friendship stadium. The impacts of this pollution could be significant on sensitive people such as the elderly, newborns and patients with acute and chronic respiratory illnesses.

Remote sensing of air pollution incorporating integrated-path differential-absorption and coherent-Doppler lidar

An innovative complex lidar system deployed on an airborne rotorcraft platform for remote sensing of atmospheric pollution is proposed and demonstrated.The system incorporates integrated-path differential absorption lidar(DIAL) and coherent-doppler lidar(CDL) techniques using a dual tunable TEA CO_(2)laser in the 9—11 μm band and a 1.55 μm fiber laser.By combining the principles of differential absorption detection and pulsed coherent detection,the system enables agile and remote sensing of atmospheric pollution.Extensive static tests validate the system’s real-time detection capabilities,including the measurement of concentration-path-length product(CL),front distance,and path wind speed of air pollution plumes over long distances exceeding 4 km.Flight experiments is conducted with the helicopter.Scanning of the pollutant concentration and the wind field is carried out in an approximately 1 km slant range over scanning angle ranges from 45°to 65°,with a radial resolution of 30 m and10 s.The test results demonstrate the system’s ability to spatially map atmospheric pollution plumes and predict their motion and dispersion patterns,thereby ensuring the protection of public safety.

Analysis of Spatial and Temporal Distribution Characteristics of Air Pollutants in Tibet

This paper takes seven cities in the Tibet Autonomous Region as the study area,and collects data from more than 20 monitoring stations covering the Tibet Autonomous Region in the ambient air quality online monitoring platform to analyze the spatial and temporal variation characteristics of PM_(10),PM_(2.5),SO_(2),NO_(2),CO and O_(3)MAD 8(ozone daily maximum 8-h average).The results show that(1)the multi-year average PM_(2.5)concentration in Tibet Autonomous Region is 12.03μg/m^(3);the multi-year average PM_(10)concentration is 28.27μg/m^(3);the multi-year average CO concentration is 0.59 mg/m^(3);the multi-year average NO_(2)concentration is 12.34μg/m^(3);the multi-year average SO_(2)concentration is 7.00μg/m^(3);the multi-year average value of O_(3)is 89.54μg/m^(3).The concentrations of atmospheric pollutants all meet the primary concentration limits of the Ambient Air Quality Standards(GB 3095-2012).(2)The air environment in the Tibet Autonomous Region in spring is relatively poor,with about 20%of excellent days and 80%of good days.The air environment is relatively good in summer,autumn and winter,with about 65%-87%of excellent days and 35%-13%of good days.The air environment quality of Tibet Autonomous Region is excellent:winter>autumn>summer>spring,and good:spring>summer>autumn>winter.(3)Except for NO_(2)which is more influenced by automobile exhaust and SO_(2)which is more influenced by man-made source in winter,the ambient air quality in Tibet Autonomous Region is less influenced by industry.The variability characteristics of the six atmospheric pollutants studied in this paper are strongly correlated with the unique natural environment of Tibet(air pressure,altitude,wind speed,temperature,precipitation,solar radiation,etc).

Atmospheric lead pollution in fine particulate matter in Shanghai, China

The Pb-monitoring program was extended for 6 years from 2002 to 2007 at 17 representative urban sites （6 traffic, 5 industrial, and 6 residential sites）, and 3 suburban sites to assess the lead pollution in fine particulate matter （PM2.5） after phasing out leaded gasoline in Shanghai. Compared with Pb levels reported in other places, the Pb pollution in Shanghai is still serious after phasing out leaded gasoline, which remains at high concentration range （213-176 ng/m^3） in PM2.5 in winter. Significant spatial variation of Pb concentrations and strong seasonal variation of higher Pb concentration in winter than that in summer were detected. The size distribution of Pb in particulate matter has a unimodat mode that peaks at approximately 0.154-1.59 μm particle diameter, indicating that Pb is mainly concentrated in fine fraction. Lead in the fine fraction is enriched by a factor of 103-104 relative to Pb abundance in crust. Eight categories of Pb pollution sources were identified in the PM2.5 in the winter of 2007 in Shanghai. The important emission sources among them are vehicle exhaust derived from combustion of unleaded gasoline, metaUurgic industry emission, and coal combustion emission.

Transport Patterns and Potential Sources of Atmospheric Pollution during the ⅩⅩⅣ Olympic Winter Games Period

The attainment of suitable ambient air quality standards is a matter of great concern for successfully hosting the ⅩⅩⅣ Olympic Winter Games(OWG). Transport patterns and potential sources of pollutants in Zhangjiakou(ZJK) were investigated using pollutant monitoring datasets and a dispersion model. The PM_(2.5) concentration during February in ZJK has increased slightly(28%) from 2018 to 2021, mostly owing to the shift of main potential source regions of west-central Inner Mongolia and Mongolian areas(2015–18) to the North China Plain and northern Shanxi Province(NCPS) after 2018.Using CO as an indicator, the relative contributions of the different regions to the receptor site(ZJK) were evaluated based on the source-receptor-relationship method(SRR) and an emission inventory. We found that the relative contribution of pollutants from NCPS increased from 33% to 68% during 2019–21. Central Inner Mongolia(CIM) also has an important impact on ZJK under unfavorable weather conditions. This study demonstrated that the effect of pollution control measures in the NCPS and CIM should be strengthened to ensure that the air quality meets the standard during the ⅩⅩⅣ OWG.

Concentrations and isotopic characteristics of atmospheric reactive nitrogen around typical sources in Beijing,China

With rapid economic growth in China, anthropogenic reactive nitrogen （Nr） emissions have more than doubled over the last two or three decades. Atmospheric Nr pollution is an environmental concern in China especially in megacities such as Beijing. In order to identify the impact of emission sources on atmospheric Nr pollution, we measured atmospheric Nr concentrations and their isotopic composition （δ15N） dynamics at three typical sites： landfill, pig farm and road traffic sites in Beijing from April 2010 to March 2011. Passive samplers were used for monitoring ammonia （NH3） and nitrogen dioxide （NO2）, two major Nr species, while their δ15N values were measured by a diffusion method combined with mass spectrometer approach. The raw water pool of the landfill and fattening house of the pig farm were important NH3 sources with mean NH3 concentrations being 2,829 and 2,369 μg/m3, respectively, while the road traffic site was a minor NH3 source （10.6 μg/m3）. NH3 concentrations at sites besides the landfill and roads were high in summer and low in winter due to the annual variation of temperature and the change of emission source intensity. In contrast, the NH3 concentrations inside the pig farm house were high in winter and low in summer, for the barn windows were open in summer and closed in winter. The mean NO2 concentrations were 89.8, 32.9 and 23.0 μg/m3 at the road traffic, the landfill and pig farm sites, respectively. Due to vehicle fuel combustion, NO2 concentration at the road traffic was the highest among the three sources, and the road traffic was a main NO2 emission source. PM10, pNH4＊ and pNO3- concentrations in particulate matter were higher in summer than in winter （except PM10 for the pig farm）. The δ15NH3 values ranged from -19.14‰ to 7.82‰, with an average of-0.05‰ for the landfill site, and the lowest values were observed in June and July. The δ15NH3 values for the pig farm site ranged from -29.78‰ to-14.05‰ with an average of-24.51‰, and the 515NH3 values were more negative in summer than in the other seasons. The （515NO2 values were -9.63%o to 7.04‰ with an average of -3.72%0 for the road traffic site. The δ15NO2 values were more negative in summer than those in the other seasons. The different δ15N values for the various Nr species in different sources may serve as important indicators for identifying atmospheric Nr sources in megacities. The results may also provide the theoretical basis for research on the atmospheric N deposition and its sources.

Concentrations,sources,and influential factors of water-soluble ions of atmospheric particles in Dunhuang Mogao Grottoes,a world heritage site in China

Atmospheric particle pollution is one of the major factors leading to degradation of ancient wall paintings,particularly heritage sites in arid and semi-arid regions.However,current systematic research on the changes,sources,and influential factors of atmospheric particulate matter and its water-soluble ion concentrations is not sufficient.Thus,the major water-soluble ion concentrations,sources,and influential factors of atmospheric particles PM_(2.5) and PM_(10)(particulate matter with an aerodynamic equivalent diameter≤2.5 and 10.0μm,respectively,in ambient air)were collected from Cave 16 and its ambient exterior environment in the Dunhuang Mogao Grottoes,China,between April 2015 and March 2016.Results showed that the concentrations of PM_(2.5) and PM_(10) inside and outside the cave were the highest in March 2016 and the lowest in December 2015.The higher particle concentration from March to May was related to the frequent occurrence of sand and dust events,and the lower particle concentration from June to September was associated with good diffusion conditions,increased precipitation,and an established cave shelterbelt.The concentration of particulate matter inside the cave was affected by the concentration of particles in the air outside the cave.Ca2+,NH+4,Na+,Cl-,and SO2-4were the main components of the total ions of PM_(2.5) and PM_(10) both inside and outside the cave.The total ions inside the cave were frequently affected by the disturbance of tourists'activities during the peak tourist season from May to August.Under the influence of dust,the total concentrations of Cl-,SO2-4,Na+,NH+4,and Ca2+in particles of different sizes inside and outside the cave increased,and the concentrations of Cl-,SO2-4,Na+,and Ca2+decreased during precipitation period.Backward air mass trajectory analysis suggested that the pollutants were mainly from Xinjiang,China.The pollutant sources of air particulates are straw burning,secondary pollution sources,soil dust,dry spring rivers,and tourist activities.

Atmospheric pollution in Beijing, China, as recorded in sediments of the Kunming Lake

The fluxes of heavy metals and magnetite, a fly-ash component, from coal burning, to sediments of the Kunming Lake in Beijing have increased measurably over the last fifty years. Ages were introduced to the sediment strata through Pb-210 geochronologies. Even with a doubling of coal usage by the year 2000, the anthropogenic metal fluxes will still be less than those recorded in metropolitan Tokyo and U.S. lakes.