Journal of Environmental Management, February 2021
Yuhao Zhao, Na Wang, Yuhang Luo, Haishan He, Lei Wu, Hongliang Wang, Qingtao Wang, Jiansheng Wu
Abstract: Previous studies on the supply and demand of ecosystem services (ES) mainly focused on inter-annual changes, and no studies have explored the impact of demographic change on the ES supply and demand on fine-grained time scales. Thus, taking Shenzhen as an example, the status of ES supply and demand, as well as diurnal population changes and their impacts on cultural services were analyzed at different time periods using mobile phone signaling data, ecological supply-demand ratio (ESDR), Geo-Informatic Tupu, InVEST model and buffer zone. The results showed that the population declines successively on workdays, weekends and holidays, and that the daytime population is greater than the nighttime. Water yield services can basically meet the demand in terms of quantity and spatial distribution, however, carbon sequestration and cultural services showed the opposite results. The main type of ESDR changes in cultural services are the mutual conversion of deficit and balance, and these are concentrated in areas with high forest coverage and small populations, but frequent population changes. In addition, when the fixed population is too large, the use of time-varying population data will conceal the impact of demographic changes on ES supply and demand, and other data are needed for auxiliary analysis. Overall, this study provides a new research perspective for the ES supply and demand and can provide a theoretical basis for refined sustainable urban management.
88. Analyzing the Contribution of Human Mobility to Changes insights from the COVID-19 Lockdown
ISPRS International Journal of Geo-Information, December 2021
Jiansheng Wu , Yun Qian, Yuan Wang, Na Wang
Abstract: During the COVID-19 lockdown in Wuhan, transportation, industrial production and other human activities declined significantly, as did the NO2 concentration. In order to assess the relative contributions of different factors to reductions in air pollutants, we implemented sensitivity experiments by Random Forest (RF) models, with the comparison of the contributions of meteorological conditions, human mobility, and emissions from industry and households between different periods. In addition, we conducted scenario analyses to suggest an appropriate limit for control of human mobility. Different mechanisms for air pollutants were shown in the pre-pandemic, pre-lockdown, lockdown, and post-pandemic periods. Wind speed and the Within-city Migration index, representing intra-city mobility intensity, were excluded from stepwise multiple linear models in the pre-lockdown and lockdown periods. The results of sensitivity experiments show that, in the COVID-19 lockdown period, 73.3% of the reduction can be attributed to decreased human mobility. In the post-pandemic period, meteorological conditions control about 42.2% of the decrease, and emissions from industry and households control 40.0%, while human mobility only contributes 17.8%. The results of the scenario analysis suggest that the priority of restriction should be given to human mobility within the city than other kinds of human mobility. The reduction in the NO2 concentration tends to be smaller when human mobility within the city decreases by more than 70%. A limit of less than 40% on the control of the human mobility can achieve a better effect, especially in cities with severe traffic pollution.
87. Does air pollution contribute to urban–rural disparity in male lung cancer diseases in China
Environmental Science and Pollution Research, November 2021
Huagui Guo, Weifeng Li, Jiansheng Wu, Hung Chak Ho
Abstract: It remains unknown whether exposure to ambient air pollution can be a mediator linking socioeconomic indicator to health outcome. The present study aims to examine the mediation effect of PM2.5 air pollution on the association between urban–rural division and the incidence (mortality) rate of male lung cancer. We performed a nationwide analysis in 353 counties (districts) of China between 2006 and 2015. A structural equation model was developed to determine the mediation effect of exposure to PM2.5. We also tested whether the findings of the mediation effect of exposure to PM2.5 are sensitive to the controls of smoking factors and additional air pollutant, and PM2.5 exposures with different lag structures. According to the results, we found that exposure to PM2.5 significantly mediated the association between urban–rural division and the incidence rate of male lung cancer. Specifically, there were significant associations between urban–rural division, exposure to PM2.5, and the incidence rate of male lung cancer, with PM2.5 exposure accounting for 29.80% of total urban–rural difference in incidence rates of male lung cancer. A similar pattern of results was observed for the mortality rate of male lung cancer. That is, there was a significant mediation effect by PM2.5 on the association of the mortality rate with urban–rural division. The findings of exposure to PM2.5 as a mediator were robust in the three sensitivity analyses. In conclusion, urban–rural difference in exposures to PM2.5 may be a potential factor that contributes to urban–rural disparity in male lung cancer diseases in China. The findings inform that air pollution management and control may be effective measures to alleviate the great difference in male lung cancer diseases between urban and rural areas in China.
Remote Sensing，November 2021
Yun Qian, Han Wang, Jiansheng Wu
Abstract: For urban waterlogging alleviation, green infrastructures have been widely concerned. How to carry out scientific green infrastructure planning becomes an important issue in flood control and disaster relief. Based on historical media records of urban waterlogging from 2017 to 2020 and combined with variables about topography, land cover and socioeconomics, we used the Radial Basis Function Neural Network (RBFNN) to conduct urban waterlogging susceptibility assessment and simulate the risk of waterlogging in different scenarios of green land configuration in Shenzhen. The results showed that: (1) high proportions of impervious surface and population could increase the risks in Luohu and Futian districts, followed by Nanshan and Baoan districts, while high proportions of green space could effectively reduce the risks in southeastern Shenzhen; (2) urban waterlogging in Luohu and Futian districts can be alleviated by strengthening green infrastructure construction while Longgang and Longhua districts should make comprehensive use of other flood prevention methods; (3) turning existing urban green space into impervious surfaces would increase the risks of waterlogging, which is more evident in places with high proportions of green space such as Dapeng and Yantian districts. The effectiveness of green infrastructures varies in different spatial locations. Therefore, more attention should be paid to protecting existing green spaces than cultivating more green infrastructures in urban waterlogging alleviation.
85. Urban road greenbelt configuration: The perspective of PM2.5 removal and air quality regulation
Environment International, December 2021
Jiansheng Wu, Keyu Luo, Yi Wang, Zhenyu Wang
Abstract: The establishment of the road green belt (RGB) is an effective means to reduce particle matter (PM2.5) emissions from road traffic. This study tested the ability of 23 common tree species in Shenzhen to reduce PM2.5 concentrations using field investigations and wind tunnel tests. The association between leaf microstructure and individual reduction ability was also analyzed. Finally, the impact of three RGB configurations (i.e., arbor, shrub, arbor + shrub) on road PM2.5 dispersion and deposition was simulated using the ENVI-met three-dimensional aerodynamic model, based on which an optimal RGB configuration was proposed. There were three key findings of the tests. First, the wind speed was the main factor affecting the PM2.5 concentration (54.2%), followed by vehicle flow (27.7%), temperature (14.2%), and time factor (7.6%). Second, the range of dry deposition velocity (Vd) was 0.04–6.4 m/s, and the dominant dust-retaining plant species were the evergreen trees, Ficus microcarpa and Ficus altissima, and the evergreen shrubs, Codiaeum variegatum and Fagraea ceilanica. A higher proportion of grooves or larger stomata would increase the probability that the blade would capture PM2.5. Third, the shrub RGB demonstrated the best performance in terms of pollutant dispersion; its PM2.5 concentration at the respiratory height (RH, 1.5 m) on the pedestrian crossing was 15–20% lower than the other RGB configurations. In terms of pollutant deposition, the arbor + shrub composite RGB was two-fold better than the other RGB configurations. Moreover, it was more advantageous to plant shrub RGBs in street canyons to achieve a balance between the lowest concentration and the largest deposition of PM2.5 pollutants. The findings of this study will facilitate the RGB configurations with good dust retention ability.
Ecological Indicators, November 2021
Jiansheng Wu, Danni Zhang, Han Wang, Xuechen Li
Abstract: Rapid industrialization and urbanization accelerate land use and land cover change, resulting in problems of stability and health with ecosystem services losses. It remains unclear and needs to be detailed discussed what spatial–temporal characteristics of the production-living-ecological spaces (PLES) would be in a rapidly developing bay area under a certain development goal. A novel future land use simulation model integrated with a dual environment evaluation system consisting of the evaluation of resources and environmental carrying capacity and territorial spatial development suitability was conducted to predict the PLES in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) in a multi-scenario view; and then we figured out the spatial–temporal changes of the PLES in the GBA during 2015–2035. Results suggest: 1) Using the DEE to determine conversion probability estimation helps to simulate and predict land use changes with high accuracy. Under the CUA scenario, the PLES account for 21.76%, 14.60% and 63.64%, respectively. The production space in Shenzhen, Hong Kong and Dongguan is dispersed, while the living space in Dongguan is clustered. The patch boundary of ecological space in Zhaoqing, Huizhou and Jiangmen would become more complex. 2) The change of the PLES in the GBA is mainly manifested by the processes of production and ecological space transferring to living space even under CUA scenario, which mainly occurs on the edge of the existing living space, especially in Zhaoqing, Conghua District of Guangzhou, Longmen County and Boluo County of Huizhou. 3) With potential conflicts between production space and ecological space, more attention should be paid to reducing the occupation of basic farmland in ecological restoration in the GBA. The future PLES in the GBA would be characterized by the conflict between the living and non-living spaces and that between productive and ecological spaces. The predicted PLES under CUA scenario may provide a spatial reference for policy-making in the future territorial spatial development and construction of ecological security patterns in the GBA.
83. Spatial-temporal change of ecosystem health across China: Urbanization impact perspective
Journal of Cleaner Production, December 2021
Jiansheng Wu, Dongjun Cheng, Yingying Xu, Qiao Huang, Zhe Feng
Abstract: Exploring the relationship between ecosystem health and urbanization is the foundation for solving the ecological and environmental problems of urban ecosystems and has both theoretical and practical significance. This paper investigates the relationship between ecosystem health and urbanization in 260 Chinese cities in the years 2000, 2005 and 2010. For each city, four aspects of ecosystem health are evaluated and three types of urbanization are measured. The paper uses piecewise linear regression to explore the spatiotemporal dynamics of the relationship between urbanization and ecosystem health at both national and regional levels. Finally, the threshold levels of urbanization that cause changes in ecosystem health responses were estimated. The results show significant negative correlations between different dimensions of urbanization and ecosystem health at the national level, with spatial urbanization having a greater effect than economic and population urbanization. The results also reveal regional and temporal differences in the correlations at both national and regional levels, along with threshold levels for the effects of urbanization. This paper aims to explore the dynamic impacts of different urbanization characteristics and stages on ecosystem health, and help in reconciling the contradictions between economy, population, land expansion, and ecosystem health in different urbanization stages by identifying the thresholds of change trends.
Land, August 2021
Keyu Luo, Zhenyu Wang, Wei Sha, Jiansheng Wu, Hongliang Wang, Qingliang Zhu
Abstract: Land suitability assessment is fundamental in space control planning and land development because of its effects on land use and urban layout. Rainstorms and waterlogging have become one of the most common natural disasters in the coastal areas of China. As a result, the concept of an ecological sponge city was incorporated into the construction of cities in the future. Taking Shenzhen–Shantou special cooperation zone (SSCZ), we constructed a storm flooding model based on the SCS flow generation model and GIS to explore the spatial distribution characteristics of the flooding risk in a rainstorm of 100-year lasting 1 h. Combined with population and economic indicators, a radial basis function (RBF) network was utilized to evaluate the environmental risk, the vulnerability of disaster-bearing bodies, and the rain–flood resilience of sponge cities. The self-organizing feature mapping (SOFM) model was used for cluster analysis. Spatial differences were found in the construction suitability of the study area. A suitable construction area (73.59% of the entire area) was located downtown. The construction of the artificial spongy body in the highest vulnerable area (3.25%) needs to be strengthened. The control construction area (3.3%) is located along the banks of the river, with relatively high risk and low resilience of flood control engineering. Ecological construction (19.85%) serves as the sponge body of ecological buffer. The factors of waterlogging, ecology, population, and economy could be integrated comprehensively by applying neural network methods for urban planning and construction.
Scientific Reports, July 2021
Jiansheng Wu, Xuechen Li, Yuhang Luo, Danni Zhang
Abstract: Since the implementation of the Chinese economic reforms. The habitat quality of coastal has gradually deteriorated with economic development, but the concept of "ecological construction" has slowed the negative trend. For quantitative analysis of the correlation between the Pearl River Delta urban expansion and changes in habitat quality under the influence of the policy, we first analyzed the habitat quality change based on the InVEST model and then measured the impact of construction land expansion on the habitat quality through habitat quality change index (HQCI) and contribution index (CI) indicators. Finally, the correlation between urbanization level and habitat quality was evaluated using geographically weighted regression (GWR) and the Self-organizing feature mapping neural network (SOFM). The results indicated that: (1) during the study period from 2000 to 2020, habitat quality declined due to urban sprawl, indicating a deterioration of ecological structure and function, and the decrease was most significant from 2000 to 2010. (2) The urbanization index had a negative effect on the habitat quality, but the negative effect have improved after 2000, reflecting the positive effect of policies such as "ecological civilization construction" (3) The implementation degree of ecological civilization varies greatly among cities in the study area: Shenzhen, Dongguan, Foshan, and Zhongshan have the best level of green development. These results reflect the positive role of policies in the prevention of damage to habitat quality caused by economic development and provide a reference for the formulation of sustainable urban development policies with spatial differences.
Journal of Cleaner Production, May 2021
Jiansheng Wu, Qingliang Zhu, Na Qiao, Zhenyu Wang, Wei Sha, Keyu Luo, Hongliang Wang, Zhe Feng
Abstract: Coal mining play a fundamental role in promoting economic and social progress. However, intensive mining operations have brought enormous ecological risks, such as landform destruction, vegetation degradation and biodiversity loss. Based on the “source-sink” landscape and ecological risk assessment theories, this study proposes a new methodology to comprehensively analyze the mechanism of ecological risk and makes quantitative evaluation taking Pingshuo coal mine area as an example from 2000 to 2017. The results prove that the “source-sink” landscape theory is more consistent with the nature of ecological process to distinguish the ecological risk in mining area. Within the study period, the main risk source of mining areas is the environmental disturbance brought by mining production with a spreading trend, while the pollution risk caused by residents’ life is relatively low but the scope is large. The ecological niche of risk sink (a place where ecological risks disappear) in the study area improved as a whole, the ecological vulnerability and exposure coefficient of risk sink shows a decreasing trend from core mine area to outside, and the trend was not obvious at the end stage, testifying the protective effect of environmental governance. The striking increase areas of comprehensive ecological risk are mostly concentrated in the surroundings of mining production expansion, testifying mining practice has a significant adverse impact on the contiguous natural ecosystem. Any kind of pressure from coal mine operation, residents’ production and natural erosion in mining area should not be ignored, and the high risk areas are markedly clustered around the risk sources.