Li Q.,Beijing Normal University |
Song J.,Beijing Normal University |
Zhang J.,China Environmental Monitoring Station |
Yu W.,Beijing Normal University |
Hu H.,The Environmental Protection Information Center
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2013
This study aims to investigate the relationship between urbanization and air pollution at the city level by analyzing annual panel data of 237 cities and total amount of 2353 samples during the period 2001-2010. Firstly, we took the unit stationary test of panel data, and then used fixed effect model and random effect model to investigate the relationship. The dependent variables included annual average concentrations of SO2, NO2, PM10 and comprehensive index, and the explanatory variables included per capita GDP, population density, proportion of secondary industry and urban area. The analysis results showed that the characteristics of relationship were dependent on types of pollutants. We found the existence of an invert U-shaped curve for SO2, which demonstrated that SO2 pollution of cities had reached the turning point, with the concentration of SO2 decreased along with the economic development. In comparison, U-shaped curves existed for NO2, PM10 and comprehensive index, which showed that the concentrations of NO2 and PM10 were still in the upward trend at current stage. Moreover, the growth of secondary industries and the expansion of urban area had strong positive relationship with the concentrations of main pollutants.
Yu D.,Nanjing University |
Yang J.,China Environmental Monitoring Station |
Li T.,Nanjing University |
Feng J.,Nanjing University |
And 2 more authors.
Environmental Science and Pollution Research | Year: 2015
The occurrence and spatial distribution of dechloranes including mirex, dechlorane plus (DP), dechlorane (Dec) 602, Dec 603, and Dec 604 in surficial sediments of Lake Taihu were investigated in this study. The concentrations of mirex and DP ranged from below detection limit (BDL) to 1.29 ng g−1 dw and 0.051 to 2.10 ng g−1 dw, respectively. Dec 602, Dec 603, and Dec 604 on the other hand, were BDL in any of the samples. The contamination levels of DP were higher than that of Mirex at 21 of all 22 sampling sites. Levels of mirex and DP in the lake sediments were correlated when an extremely high mirex value was removed. Both mirex and DP levels were correlated with the amount of organic matters in the sediment samples. Spatial distribution of mirex and DP suggested that these two chemicals in the lake had similar input sources except for one site. Comparison to previously reported flame retardants’ levels in the sediments shows that DP levels were similar with the levels of tetrabromobisphenol A, hexabromocyclododecane but lower than PBDEs and organophosphates levels in Lake Taihu. The higher levels in the north-east part of Lake Taihu adjacent to two major cities: Wuxi and Suzhou, indicated that city effluent might be a major source for DP contamination in the lake. © 2014, Springer-Verlag Berlin Heidelberg.
Li Q.,China Environmental Monitoring Station |
Hu H.,The Environmental Protection Information Center |
Luo H.,China Environmental Monitoring Station |
Lin L.,China Environmental Monitoring Station |
And 3 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2015
This study estimates the dynamic two-way coupling relationship between economic growth and environmental pollution based on the panel data of 31 provinces during 1985-2011 using PVAR model. Econometric methods are used in eastern, central and western regions to test the data validation and cointegration between variables, and then analyze the impulse response functions between per capita GDP and 12 environmental pollution indices, including industrial and domestic pollution, waste water discharges and exhaust emissions. The estimate results show that apart from the marked impact from economic growth on environmental pollution, environmental pollution also has significant feedback mechanism to the regional economic growth. In addition, this two-way coupling relationship shows significant regional differences. The contradiction between economic growth and environmental pollution in the western region is the most serious, while the central region is moderate and the contradiction is the lowest in eastern region. The variance decomposition result indicates that, at present, economic growth is the main contributor to explain the forecasting mean square error of the environmental pollution, but the feedback mechanism is relatively weak. ©, 2015, Science Press. All right reserved.