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Zhang X.,Nanjing University | Jiang H.,Nanjing University | Jiang H.,Zhejiang Agriculture And forestry University | Jin J.,Nanjing University | And 2 more authors.
Atmospheric Environment | Year: 2012

Acid rain is a major regional-scale environmental problem in China. To control acid rain pollution and to protect the ecological environment, it is urgent to document acid rain patterns in various regions of China. Taking Liaoning Province as the study area, the present work focused on the spatial and temporal variations of acid rains in northeastern China. It presents a means for predicting the occurrence of acid rain using geographic position, terrain characteristics, routinely monitored meteorological factors and column concentrations of atmospheric SO2 and NO2. The analysis applies a decision tree approach to the foregoing observation data. Results showed that: (1) acid rain occurred at 17 stations among the 81 monitoring stations in Liaoning Province, with the frequency of acid rain from 0 to 84.38%; (2) summer had the most acid rain occurrences followed by spring and autumn, and the winter had the least; (3) the total accuracy for the simulation of precipitation pH (pH ≤ 4.5, 4.5 < pH ≤ 5.6, and pH > 5.6) was 98.04% using the decision tree method known as C5. The simulation results also indicated that the distance to coastline, elevation, wind direction, wind speed, rainfall amount, atmospheric pressure, and the precursors of acid rain all have a strong influence on the occurrence of acid rains in northeastern China. © 2011 Elsevier Ltd. Source

Zhao Q.,CAS Shenyang Institute of Applied Ecology | Zhao Q.,University of Chinese Academy of Sciences | Ma J.,CAS Shenyang Institute of Applied Ecology | Wen Q.-C.,CAS Shenyang Institute of Applied Ecology | And 4 more authors.
Journal of Ecology and Rural Environment | Year: 2010

Aiming at the problem of lack of water monitoring data of medium and small river basins in the countryside of North China, a project was carried out based on the findings of field surveys and the local statistics yearbooks, to calculate agricultural non-point source pollution load of 10 administrative villages in Dasuhe Township, using the export coefficient method, and in verification of the data obtained in the field survey and their relationship with pollution load, evaluation of the pollution sources was done, using the equiscalar pollution loading method, to obtain comparative equiscalar pollution loads on the same scale. Cluster analysis of the findings and results were obtained. The 10 villages were divided into 4 types in terms of agricultural non-point source pollution, and characteristics of each pollution source was analyzed. Results of the evaluation show that the Dasuhe Village ranked first in contribution to the load of domestic pollution and livestock dejecta pollution, and the Xiaosuhe Village did in contribution of the load of farmland chemical fertilizer pollution. The cluster analysis also demonstrates that the mean value of the equiscalar pollution loads of the 4 types of agricultural nonpoint source pollution was 51. 05,95. 80,236. 41,185. 69 m3, which indicates that relative differences are exsiting between villages in agricultural non-point source pollution. Source

Zhang X.,Nanjing University | Jiang H.,Nanjing University | Jiang H.,Zhejiang Agriculture And forestry University | Zhang Q.,Liaoning Environmental Monitoring Center | Zhang X.,Beijing Normal University
Atmospheric Research | Year: 2012

The samples of rainwater were collected at two urban sites and one rural site in Dalian from January to December 2007, and precipitation pH, conductivity, and main chemical components were analyzed. The dominant ions in rainwater were SO 4 2-, NO 3 -, NH 4 +, Cl -, Ca 2+ and Na +, which accounted for 92.03% of the total ions. Winter and spring had high concentrations of chemical components, while autumn and summer had relative low values. The dominant neutralization substances were NH 4 +, Ca 2+, and Mg 2+, and presented relatively lower neutralization capability than the other major acid rain city in north China. This caused precipitation was typically acidic with pH 4.79. Downtown has obvious lower precipitation pH, higher electrical conductivity value, higher concentrations of chemical components, and higher neutralizing capability than rural area. Furthermore, the possible common sources of major ions were identified based on backward trajectory analysis, correlation analysis, and source contribution. It presented that the chemical ion concentrations were influenced not only by local emissions but also transferred materials by wind from remote areas. SO 4 2-, NO 3 -, and NH 4 + were mainly from human activities, Ca 2+, Mg 2+, and K + were soil derived, Na + and Cl - were marine source, and the contribution of anthropogenic activities was also considerable for Cl -. © 2012 Elsevier B.V. Source

Wen Q.,CAS Shenyang Institute of Applied Ecology | Wen Q.,Liaoning Environmental Monitoring Center | Chen X.,CAS Shenyang Institute of Applied Ecology | Shi Y.,CAS Shenyang Institute of Applied Ecology | And 2 more authors.
Procedia Environmental Sciences | Year: 2011

The composition and spatial pattern of agricultural non-point source (NPS) pollution was studied in Liaohe River basin which is representative of areas of intensive NPS pollution in Northeast China. Selecting COD and ammonia nitrogen as the major pollutants, the export coefficient method and GIS spatial analysis methods were utilized to analyze the component composition and spatial distribution characteristics of NPS pollution in Liao River basin. The results showed that farmland runoff was the most significant source for the agricultural NPS pollution in the study area. Over 60 percents of the pollution loading was distributed in the Liaohe River mainstream area, and the pollution intensities were stronger in Hunhe River downstream and Liaohe River stem downstream plain sub-basins in Central-Western Liaoning province than in Hunhe River upstream and Taizihe hilly sub-basins in eastern Liaoning province. © 2011 Published by Elsevier Ltd. Source

Zhang L.-J.,Nanjing University | Zhang X.-Y.,Nanjing University | Jiang H.,Nanjing University | Jiang H.,Zhejiang Agriculture And forestry University | Zhang Q.-X.,Liaoning Environmental Monitoring Center
Huanjing Kexue/Environmental Science | Year: 2013

To understand the origin and chemical characteristics of precipitation in Shenyang, about 25 rainwater samples were collected in 2007. The pH of samples varied from 4.89 to 8.02, with the volume-weighted average of 6.89. The results showed that the concentration of the sum of anions and cations in Shenyang was higher than those in southern cities such as Hangzhou, whereas the acidification of rainwater was not very serious in Shenyang. The volume-weighted average concentrations of SO42- and Cl- were 330.00 μeq·L-1 and 85.05 μeq·L-1, with the percent contribution to anions of 60.32% and 15.55%, respectively. Ca2+ and NH4+ were the main cations with contribution of 49.51% and 29.78%, respectively. The seasonal variations of ions showed that the concentrations were higher in autumn and winter than in spring and summer. Investigations of fractional acidity (FA), neutralization factors (NF), and correlation coefficients among ionic constituents indicated that high pH values were controlled by the neutralization caused by the alkaline materials but not by the absence of acidic materials. Results of NF indicated that NH4+ and Ca2+ were the dominant neutralization substances. Calculation of enrichment factors for rainwater components relative to soil and seawater indicated that SO42- and NO3- were mostly attributed by the anthropogenic activities, 53.1% of Cl- originated from sea sources, and NH4+ and K+ came from the soils and human activities. Source

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