scholarly journals Integrating Sustainability Assessment into Decoupling Analysis: A Focus on the Yangtze River Delta Urban Agglomerations

2020 ◽  
Vol 12 (19) ◽  
pp. 7872
Author(s):  
Yijia Huang ◽  
Jiaqi Zhang ◽  
Jinqun Wu

Rapid urbanization has led to a growing number of environmental challenges in large parts of China, where the Yangtze River Delta (YRD) urban agglomerations serve as a typical example. To evaluate the relationship between environmental sustainability gaps and urbanization in 26 cities of the YRD, this study revisited the environmental sustainability assessment (ESA) by combining the metrics of environmental footprints and planetary boundaries at the city level, and then integrated the footprint-boundary ESA framework into decoupling analysis. The results demonstrated considerable spatiotemporal heterogeneity in the environmental sustainability of water use, land use, carbon emissions, nitrogen emissions, phosphorus emissions and PM2.5 emissions across the YRD cities during the study period 2007–2017. Decoupling analysis revealed a positive sign that more than half of the 26 cities had achieved the decoupling of each category of environmental sustainability gaps from urbanization since 2014, especially for nitrogen and phosphorus emissions. On the basis of ESA and decoupling analysis, all the cities were categorized into six patterns, for which the optimal pathways towards sustainable development were discussed in depth. Our study will assist policy makers in formulating more tangible and differentiated policies to achieve decoupling between environmental sustainability gaps and urbanization.

2016 ◽  
Author(s):  
Lei Shu ◽  
Min Xie ◽  
Tijian Wang ◽  
Pulong Chen ◽  
Yong Han ◽  
...  

Abstract. Severe high ozone (O3) episodes usually have close relations to synoptic systems. A regional continuous O3 pollution episode is detected over the Yangtze River Delta (YRD) region in China during August 7–12, 2013, in which the O3 concentrations in more than half of the cities exceeding the national air quality standard. The maximum hourly concentration of O3 reaches 167.1 ppb. By means of the observational analysis and the WRF/CMAQ numerical simulation, the characteristics and the essential impact factors of the typical regional O3 pollution is integratedly investigated. The observational analysis shows that the atmospheric subsidence dominated by Western Pacific subtropical high plays a crucial role in the formation of high-level O3. The favorable weather conditions, such as extremely high temperature, low relative humidity and weak wind speed, caused by the abnormal strong subtropical high are responsible for the trapping and the chemical production of O3 in the boundary layer. In addition, when the YRD cities at the front of Typhoon Utor, the periphery circulation of typhoon system can enhance the downward airflows and cause worse air pollution. But when the typhoon system weakens the subtropical high, the prevailing southeasterly surface wind leads to the mitigation of the O3 pollution. The Integrated Process Rate (IPR) analysis incorporated in CMAQ is applied to further illustrate the combined influence of subtropical high and typhoon system in this O3 episode. The results show that the vertical diffusion (VDIF) and the gas-phase chemistry (CHEM) are two major contributors to O3 formation. During the episode, the contributions of VDIF and CHEM to O3 maintain the high values over 10 ppb/h in Shanghai, Hangzhou, and Nanjing. On August 10–11, the cities close to the sea are apparently affected by the typhoon system, with the contribution of VDIF increasing to 28.45 ppb/h in Shanghai and 19.76 ppb/h in Hangzhou. When the YRD region is under the control of the typhoon system, the contribution values of all individual processes decrease to a low level in all cities. These results provide an insight for the O3 pollution synthetically impacted by the Western Pacific subtropical high and the tropical cyclone system.


2013 ◽  
Vol 13 (8) ◽  
pp. 21507-21540
Author(s):  
X. Fu ◽  
S. X. Wang ◽  
Z. Cheng ◽  
J. Xing ◽  
B. Zhao ◽  
...  

Abstract. During 1 to 6 May 2011, a dust event was observed in the Yangtze River Delta region (YRD). The highest PM10 concentration reached over 1000 μg m−3 and the visibility was below 3 km. In this study, the Community Multi-scale Air Quality modeling system (CMAQ5.0) coupled with an in-line windblown dust model was used to simulate the formation, spatial and temporal characteristics of this dust event, and analyze its impacts on deposition and photochemistry. The threshold friction velocity for loose smooth surface in the dust model was revised based on Chinese data to improve the model performance. The comparison between predictions and observations indicates the revised model can reproduce the transport and pollution of the event. The simulation results show that the dust event was affected by formation and transport of Mongolian cyclone and cold air. Totally about 695 kt dust particles (PM10) were emitted in Xinjiang Province and Mongolia during 28 to 30 April, the dust band swept northern, eastern China and then arrived in the YRD region on 1 May 2011. The transported dust particles increased the mean surface layer concentrations of PM10 in the YRD region by 372% during 1 to 6 May and the impacts weakened from north to south due to the removal of dust particles along the path. Accompanied by high PM concentration, the dry deposition, wet deposition and total deposition of PM10 in the YRD reached 184.7 kt, 172.6 kt and 357.32 kt, respectively. These deposited particles are very harmful because of their impacts on urban environment as well as air quality and human health when resuspending in the atmosphere. Due to the impacts of mineral dust on atmospheric photolysis, the concentrations of O3 and OH were reduced by 1.5% and 3.1% in the whole China, and by 9.4% and 12.1% in the YRD region, respectively. The work of this manuscript is meaningful for understanding the dust emissions in China as well as for the application of CMAQ in Asia. It is also helpful to understand the formation mechanism and impacts of dust pollution in the YRD.


Land ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 91
Author(s):  
Jinfeng Ma ◽  
Weifeng Li ◽  
Zhao Wang ◽  
Liang He ◽  
Lijian Han

Although urban agglomerations are vital sites for national economic development, comprehensive multidimensional investigations of their performance are lacking. Accordingly, we examined land use efficiency from multiple perspectives in two of the earliest developed and most advanced urban agglomerations in China, the Beijing–Tianjin–Hebei (BTH) region and the Yangtze River Delta (YRD), using different metrics, including trans-regional drivers of the spatial allocation of construction land. We found that: (1) The land use efficiency of urban agglomerations was context dependent. Whereas it was higher in the Beijing–Tianjin–Hebei region for population density per unit area of construction land than in the Yangtze River Delta region, the opposite was true for gross domestic production. Thus, a single aspect did not fully reflect the land use efficiency of urban agglomerations. (2) The land use efficiency of the two urban agglomerations was also scale dependent, and in the Yangtze River Delta region, the use of multiple metrics induced variations between aggregate and local measures. Median values for the land use efficiency of cities within an urban agglomeration were the most representative for comparative purposes. (3) The drivers of the spatial allocation of construction land were trans-regional. At the regional scale, most topographical factors were restrictive. Major regional transport networks significantly influenced the occurrence of construction land near them. Dominant cities and urban areas within each city exerted remote effects on non-dominant cities and rural areas. In principle, the median value can be considered a promising metric for assessing an urban agglomeration’s performance. We suggest that stringent management of land use in areas located along regional rail tracks/roadways may promote sustainable land use.


2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Lei Ye ◽  
Lingqian Hu

An outbreak of atypical pneumonia, now called COVID-19 and known to be caused by the novel coronavirus SARS-CoV-2, first detected in Wuhan, Hubei Province of the People’s Republic of China in December 2019 and afterwards rapidly spread worldwide. Wuhan and the Yangtze River Delta (YRD) region implemented first-level public health emergency responses to stop the spread of the virus on January 23rd, 2020. We tracked the geographical gravity centre of the disease and calculated spatial autocorrelation to explore the spatiotemporal patterns of distribution of imported and locally disseminated COVID-19 cases under the emergency-response control measure. We also applied polynomial regression analysis to estimate the trend of the COVID-19 in the YRD region before and after the control activities against the spread of the infection were instituted. The results show that the control measures applied have been effective. And, in the YRD region, areas with a large influx of population flow from Wuhan and Hubei Province had high risks of COVID-19. Therefore, identification of the spatiotemporal trends should be the first step when developing effective policies to manage and control any new epidemic. The results are not only informative locally but also useful for the rest of the world.


2019 ◽  
Vol 8 (4) ◽  
pp. 8255-8259

Aerosols played an important role in climate change during recent years in China. Many kinds of researches in different areas in China, particularly over the Yangtze River Delta (YRD) region in East China is measured during the period from January 2013 to December 2015. The Moderate Resolution Imaging Spectroradiometer (MODIS) derived aerosol optical depth (AOD), particulate matter concentrations (PM2.5) and surface black carbon (BCS) was used in this study. Nanjing, Hangzhou, Shanghai, and Ningbo have been selected in this research as they are the major cities of the YRD region that represents different environments. Variation of AOD550, Ångström exponent (AE470-660) and PM2.5 are mainly discussed, and meanwhile, the relationship that exists between them and with the meteorology is also discussed in this work. Apart from this, the impact of visibility and water vapor are also considered to examine the influence on optical properties. The data and analysis indicate that urban cities have a higher value of AOD than rural background cities. High AOD was noticed in summer than in other seasons. AOD usually has a negative relationship with AE, except in summer. Similarly, the PM2.5 has a negative relationship with AOD, whereas, BCS has a positive correlation with AOD. Further, it was observed that the rise in temperature resulted in high AOD concentration. The visibility has negative effect on AOD, whereas, AQI follows similar pattern as that of visibility.


2011 ◽  
Vol 11 (1) ◽  
pp. 951-983 ◽  
Author(s):  
C. Huang ◽  
C. H. Chen ◽  
L. Li ◽  
Z. Cheng ◽  
H. L. Wang ◽  
...  

Abstract. The purpose of this study is to develop an emission inventory for major anthropogenic air pollutants and VOC species in the Yangtze River Delta (YRD) region for the year 2007. A "bottom-up" methodology was adopted to compile the inventory based on major emission sources in the sixteen cities of this region. Results show that the emissions of SO2, NOx, CO, PM10, PM2.5, VOCs, and NH3 in the YRD region for the year 2007 are 2391.8 kt, 2292.9 kt, 6697.1 kt, 3115.7 kt, 1510.8 kt, 2767.4 kt, and 458.9 kt, respectively. Ethylene, mp-xylene, o-xylene, toluene, and 1,2,4-trimethylbenzene, 2,4-dimethylpentane, ethyl benzene, propylene, 1-pentene, and isoprene are the key species contributing 77% to the total OFPs. The spatial distribution of the emissions shows the emissions and OFPs are mainly concentrated in the urban and industrial areas along the Yangtze River and around the Hangzhou Bay. The industrial sources including power plant, other fuel combustion facilities, and non-combustion processes contribute about 97%, 86%, 89%, 91%, and 69% of the total SO2, NOx, PM10, PM2.5, and VOC emissions. Vehicles take up 12.3% and 12.4% of the NOx and VOC emissions, respectively. Regarding OFPs, chemical industry, domestic use of paint and printing, and gasoline vehicle contribute 38.2%, 23.9%, and 11.6% to the ozone formation in the YRD region.


2021 ◽  
Author(s):  
Ziwu Pan ◽  
Jun Zhu ◽  
Zhenzhen Liu ◽  
Fen Qin

Abstract In recent years, the process of urbanization in China has accelerated, and changes in the underlying surface have caused the difference in average temperature between built-up areas and suburbs to increase, resulting in an urban heat island effect, which has become an important environmental issue for today's urban sustainable development. The Yangtze River Delta urban agglomeration region is the fastest-growing region in China, with economically developed and populous cities such as Shanghai, Nanjing and Suzhou. It has become one of the six major urban agglomerations in the world, and its heat island effect is particularly prominent. The single urban heat island phenomenon gradually evolves into the urban agglomeration heat island phenomenon with urbanization. However, the dynamic transfer process of key blue-green space landscapes that can alleviate land surface temperature (LST) and regional thermal environment (RTE) is still poorly understood, especially in the context of urban agglomerations. With the approval of the State Council on the development plan of the Huaihe River Ecological Economic Belt, the construction of which has been officially upgraded to a national strategy. The Eastern HaiJiang River and Lake Linkage Zone (EJRLLZ) emphasizes strengthening the docking and interaction with the surrounding areas such as the Yangtze River Delta and the Wanjiang City Belt. With the diffusion of the heat island effect of the Yangtze River Delta urban agglomeration, as one of the areas with great potential development around the world-class urban agglomeration, the rich water body and green space in the ERLLZ area are also destroyed and affected. Therefore, we take this region as a case to further quantify the impact of urbanization and urban agglomeration development on the dynamics and evolution of blue-green space.


2021 ◽  
Vol 13 (21) ◽  
pp. 4322
Author(s):  
Yingchun Bian ◽  
Ying Zhao ◽  
Heng Lyu ◽  
Fei Guo ◽  
Yunmei Li ◽  
...  

The Yangtze River Delta (YRD) is one of the regions with the most intensive human activities. The eutrophication of lakes in this area is becoming increasingly serious with consequent negative impacts on the water supply of the surrounding cities. But the spatial-temporal characteristics and driving factors of the trophic state of the lake in this region are still not clearly addressed. In this study, a semi-analytical algorithm for estimating the trophic index (TSI) using particle absorption at 645 nm based on MODIS images is proposed to monitor and evaluate the trophic state of 41 large lakes (larger than 10 km2) in the YRD from 2002 to 2020. The performance of the proposed algorithm is evaluated using an independent dataset. Results showed that the root-mean-square error (RMSE) of the algorithm is less than 6 and the mean absolute percentage error (MAPE) does not exceed 8%, indicating that it can be applied for remotely deriving the TSI in the YRD. The spatial-temporal patterns revealed that there were significantly more lakes with moderate eutrophication in the Lower Yangtze River (LYR) than in the Lower Huaihe River (LHR). The overall average value of the TSI reaches a maximum in summer and a minimum in winter. The TSI value in the YRD over the period 2002–2020 showed a downward trend, especially after 2013. Individually, 33 lakes showed a downward trend and 8 lakes showed an upward trend. Furthermore, marked seasonal and interannual temporal variations can be clearly observed in the LYR and LHR and the sum of the variance contributions of seasonal and interannual components is more than 50%. Multiple linear regression analysis showed that human activities can explain 65% of the variation in the lake TSI in the YRD.


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