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Li Q.,Chang'an University | Wang W.,Xian Environmental Protection Bureau | Duan L.,Xian Environmental Protection Bureau | Fu G.,Xian Environmental Monitoring Station
ISWREP 2011 - Proceedings of 2011 International Symposium on Water Resource and Environmental Protection | Year: 2011

Taking the Blown-sand Region of the Northern Shaanxi Province for example, studying on migration and transformation rule of farming area's nitrogen in vadose zone, this paper simulates the migration and transformation rule of farming area's nitrogen in vadose zone with the methods of field sampling, indoor tests analysis and numerical simulation. The results showed that the content of ammonia decreased rapidly, removed down slowly and accumulated in topsoil when ammonia nitrogen entered into farming soil. Nitrite and nitrate accumulated in soil profile and migration velocity accelerated with soil water moving downwards. Moreover, the nitrogen flux increased as time went by. The simulation results demonstrated that nitrogen went into groundwater in the form of nitrite nitrogen and nitrate nitrogen, with the nitrate primarily and its transfer speed greatly influenced by lithology. This paper established the coupled model of vadose zone water and "N" migration and transformation to provide early warning platform for groundwater pollution and protection of the studying area in the future, which is of important practical significance. © 2011 IEEE.


Zhang P.,Polytechnic University of Mozambique | Zhang P.,China Agricultural University | He L.,Xian Environmental Monitoring Station | Fan X.,Wuhan University | And 5 more authors.
Sustainability (Switzerland) | Year: 2015

Unreasonable land use planning can reduce ecosystem service value and result in unsustainable land use. In this paper, the changes of ecosystem service value were investigated by using the GIS and dynamic simulation model of land use in Miyun of Beijing, China, based on the land use at four time points including 1991, 2006, 2021 and one improved scenario, respectively. The results showed the total ecosystem service value of Miyun was about 2968.34 million Yuan in 1991, 3304.72 million Yuan in 2006, 3106.48 million Yuan in 2021, and 3759.77 million Yuan in the improved scenario. In terms of ecosystem service function, the functions of water supply and soil formation and retention accounted for the largest proportion, which were 19.99% and 14.58% respectively; whereas the functions of food supply and recreation and culture were only 1.83% and 5.99% respectively. Coefficients of sensitivity for forest cover, water bodies and arable land were relatively large, which were 0.73, 0.28 and 0.14, respectively. The contribution factors of total ecosystem service value with the land use change during different periods were mainly the unused land to forest cover and arable land, which respectively accounted for more than 63% and 21% of the contribution rate. These results suggested that sustainable land use planning should be undertaken with emphasis on vegetation restoration and protection of water bodies. © 2015 by the authors.


Zhang P.,Polytechnic University of Mozambique | Hong B.,Northwest University, China | He L.,Xi'an Environmental Monitoring Station | Cheng F.,Guangxi University | And 3 more authors.
International Journal of Environmental Research and Public Health | Year: 2015

PM2.5 pollution has become of increasing public concern because of its relative importance and sensitivity to population health risks. Accurate predictions of PM2.5 pollution and population exposure risks are crucial to developing effective air pollution control strategies. We simulated and predicted the temporal and spatial changes of PM2.5 concentration and population exposure risks, by coupling optimization algorithms of the Back Propagation-Artificial Neural Network (BP-ANN) model and a geographical information system (GIS) in Xi’an, China, for 2013, 2020, and 2025. Results indicated that PM2.5 concentration was positively correlated with GDP, SO2, and NO2, while it was negatively correlated with population density, average temperature, precipitation, and wind speed. Principal component analysis of the PM2.5 concentration and its influencing factors’ variables extracted four components that accounted for 86.39% of the total variance. Correlation coefficients of the Levenberg-Marquardt (trainlm) and elastic (trainrp) algorithms were more than 0.8, the index of agreement (IA) ranged from 0.541 to 0.863 and from 0.502 to 0.803 by trainrp and trainlm algorithms, respectively; mean bias error (MBE) and Root Mean Square Error (RMSE) indicated that the predicted values were very close to the observed values, and the accuracy of trainlm algorithm was better than the trainrp. Compared to 2013, temporal and spatial variation of PM2.5 concentration and risk of population exposure to pollution decreased in 2020 and 2025. The high-risk areas of population exposure to PM2.5 were mainly distributed in the northern region, where there is downtown traffic, abundant commercial activity, and more exhaust emissions. A moderate risk zone was located in the southern region associated with some industrial pollution sources, and there were mainly low-risk areas in the western and eastern regions, which are predominantly residential and educational areas. © 2015 by the authors; licensee MDPI, Basel, Switzerland.


PubMed | Northwest University, China, Polytechnic University of Mozambique, China Agricultural University, Guangxi University and Xian Environmental Monitoring Station
Type: Journal Article | Journal: International journal of environmental research and public health | Year: 2015

PM2.5 pollution has become of increasing public concern because of its relative importance and sensitivity to population health risks. Accurate predictions of PM2.5 pollution and population exposure risks are crucial to developing effective air pollution control strategies. We simulated and predicted the temporal and spatial changes of PM2.5 concentration and population exposure risks, by coupling optimization algorithms of the Back Propagation-Artificial Neural Network (BP-ANN) model and a geographical information system (GIS) in Xian, China, for 2013, 2020, and 2025. Results indicated that PM2.5 concentration was positively correlated with GDP, SO, and NO, while it was negatively correlated with population density, average temperature, precipitation, and wind speed. Principal component analysis of the PM2.5 concentration and its influencing factors variables extracted four components that accounted for 86.39% of the total variance. Correlation coefficients of the Levenberg-Marquardt (trainlm) and elastic (trainrp) algorithms were more than 0.8, the index of agreement (IA) ranged from 0.541 to 0.863 and from 0.502 to 0.803 by trainrp and trainlm algorithms, respectively; mean bias error (MBE) and Root Mean Square Error (RMSE) indicated that the predicted values were very close to the observed values, and the accuracy of trainlm algorithm was better than the trainrp. Compared to 2013, temporal and spatial variation of PM2.5 concentration and risk of population exposure to pollution decreased in 2020 and 2025. The high-risk areas of population exposure to PM2.5 were mainly distributed in the northern region, where there is downtown traffic, abundant commercial activity, and more exhaust emissions. A moderate risk zone was located in the southern region associated with some industrial pollution sources, and there were mainly low-risk areas in the western and eastern regions, which are predominantly residential and educational areas.


Zhang P.,Polytechnic University of Mozambique | He L.,Xi'an Environmental Monitoring Station | Zhang T.,Northeast Normal University | Huo P.,Tsinghua University
Open Chemical Engineering Journal | Year: 2014

The unreasonable agricultural management measure is the main cause of the risk of nitrogen and phosphorus losses. The objective of this paper was to evaluate the impacts of agricultural management practices on the risk of nitrogen and phosphorus losses at catchment scales based on GIS and integrated index models. The results showed that 93.1% of the catchment was no risk and low risk area, while 6.9% for medium and high risk of nitrogen and phosphorus losses. Spatial analysis of risk index indicated that different agricultural management practices lead to number and proportion of grids are different. At very high risk area, about 599 of grid number is only for the actual management practice, accounting for 0.22% of the total, while at very low risk area, 165884.00 and 60.51% for river buffer zone respectively. Control effect of different agricultural management practices for risk of nitrogen and phosphorus losses is better, which very low and low risk areas of based fertilizer applied deeply and buffer zone construction accounted for 98% and 95.6%, and the control effect sorted as follows: base fertilizer applied deeply> construction of river buffer zone> reduced nitrogen application> reduced phosphorus application. © Zhang et al.; Licensee Bentham Open.


Zhou B.-H.,Xi'an University of Architecture and Technology | Zhou B.-H.,Baoji University of Arts And Sciences | Zhang C.-Z.,Xi'an University of Architecture and Technology | Jiang J.-L.,Xi'an University of Architecture and Technology | And 5 more authors.
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2012

A high volume active air sampler was used to collect gaseous and particulate phase air samples in Xi'an from August 2008 to July 2009 to study the seasonal variations of atmospheric polybrominated diphenyl ethers (PBDEs). The total concentration of PBDEs (gas plus particle phase) ranged from 21.38 to 161.84 pg/m 3, with an average of 66.34 pg/m 3. The highest concentrations of atmospheric PBDEs were measured in winter, seasonal trends of PBDEs in particulate phase was similar to total suspended particulate (TSP), but PBDEs in gaseous phase had no significant seasonal variation. Partial correlation analysis showed that the total concentration and particle phase concentration of PBDEs positively correlated with air pressure, and negatively correlated with temperature. This indicates the atmospheric PBDEs concentration was mainly influenced by air pressure and temperature in Xi'an. The general population's inhalation exposure of PBDEs was calculated referencing BDE-99 inhalation human exposure assessment. The total intake of BDE-99 in normal children and adults in Xi'an was lower than the maximum allowable intake of 260 pg/(kg·d) proposed by De Winter-Sorkina.


Xu H.M.,CAS Institute of Earth Environment | Cao J.J.,CAS Institute of Earth Environment | Cao J.J.,Xi'an Jiaotong University | Ho K.F.,CAS Institute of Earth Environment | And 10 more authors.
Atmospheric Environment | Year: 2012

Daily concentrations of lead (Pb) were determined for PM2.5 samples collected from an urban location in Xi'an, China from 2007 to 2009 to assess the effects of the phasing out of leaded gasoline in 2000. The Pb concentrations (annual average: 0.306 μg m-3, range: below detection limit to 2.631 μg m-3) have declined after the phasing out of leaded gasoline, but the concentrations were still higher than those reported in many other cities. Seasonal variations of Pb were significant, with high concentrations in winter, presumably due to the burning of coal, and low concentrations in summer, due to a deep mixed layer and scavenging of aerosols by precipitation. Correlation analyses and enrichment factor calculations both indicated that anthropogenic sources had a large influence on atmospheric Pb. The lead isotope ratios were low in winter (the average 207Pb/206Pb ratio was 0.843 ± 0.032; 208Pb/206Pb was 1.908 ± 0.058) and high in summer (207Pb/206Pb was 0.860 ± 0.032; 208Pb/206Pb was 2.039 ± 0.057), suggesting that coal combustion was the major Pb source in winter and vehicular emission was the major Pb source in summer. Positive Matrix Factorization receptor model indicated that there were five major sources for Pb in PM2.5. Coal combustion was the major contributor, accounting for 39.0% PM2.5 mass, followed by vehicular emissions (30.4%). Other contributors included 17.8% from industrial emissions, 11.6% from biomass burning, and 1.2% from fugitive dust. © 2011 Elsevier Ltd.


Zhang T.,CAS Institute of Earth Environment | Cao J.J.,CAS Institute of Earth Environment | Cao J.J.,Xi'an Jiaotong University | Tie X.X.,CAS Institute of Earth Environment | And 9 more authors.
Atmospheric Research | Year: 2011

Daily PM2.5 and water-soluble inorganic ions (Na+, NH4 +, K+, Mg2+, Ca2+, Cl-, NO3 - and SO4 2-) were collected in Xi'an (34.23°N, 108.88°E), China from March 2006 to March 2007. PM2.5 was collected using battery-powered mini-volume samplers. And the ions were determined by ion chromatography from the measured aerosol mass. The annual average mass concentration of PM2.5 was found to be 194.1±78.6μgm-3, which exceeded substantially the international guidelines for health concerns. The seasonal average mass concentration of PM2.5 was highest in winter (266.8μgm-3) and lowest in summer (138.6μgm-3). The three highest abundant ions were SO4 2-, NO3 -, and NH4 +, with average concentrations of 35.6±19.5μgm-3, 16.4±10.1μgm-3, and 11.4±6.8μgm-3, which were accounted for 18.7%, 8.0%, and 5.7% of the PM2.5 mass, respectively. The major ions were in the species of (NH4)2SO4, NH4HSO4 and NH4NO3, and their concentrations were highest in winter, due to high coal combustion. The concentrations of Ca2+ were higher in spring than other seasons, due to the higher mineral dust concentrations. Ca2+ was strongly correlated with CO3 2-, which was calculated as the difference in the measured cations minus anions. Ion balance calculations indicate that the PM2.5 was acidic, and this result is consistent with the measurement of pH values. Sulfur oxidation ratio was higher in summer and autumn, which implies that the formation of secondary sulfate-rich particles is favored by warm and relatively moist weather. Nitrogen oxidation ratio was highest in autumn. © 2011 Elsevier B.V.

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