Science of The Total Environment, December 2022
Tengyun Yi, Han Wang, Chang Liu, Xuechen Li, Jiansheng Wu
Abstract: Rapid urbanization has changed the urban spatial form, which directly leads to the emergence of urban informal settlements, and the impact on ecological environment is manifested as the obvious deterioration of urban thermal environment. The thermal environment of informal settlements, which are called urban villages in China, is seriously deteriorated. In the process of urban renewal, we should pay attention to the thermal environment effect of urban villages and promote the sustainable development of cities. However, at present there are few studies on the differences of thermal comfort among urban settlements. Taking Shenzhen as an example city, this paper distinguished several scopes such as urban villages, formal settlements and non-urban areas, then analyzed the pattern characteristics of urban thermal comfort by using the Modified Temperature and Humidity Index (MTHI), and finally explored the spatial relationship between thermal comfort and various environmental factors through spatial regression models. The results show that (1) thermal comfort has significant spatial autocorrelation and the thermal environment centers are clustered in built-up areas of Shenzhen city. The overall MTHI of urban villages is relatively the highest, and the dominant thermal comfort level in summer is sultry and hot. (2) According to the Spatial Error Model, the green space coverage represented by NDVI has the strongest mitigation effect on urban thermal comfort, and the building density has an obvious aggravating effect on the muggy environment. Both of them have more obvious effects on the thermal comfort of informal settlements. (3) The current thermal environment of urban settlements cannot be ignored, especially in urban villages. In the process of urban renewal, heat dissipation should be considered emphatically. Increasing urban green area and decreasing building density will help to improve urban thermal environment. The study can provide suggestions for urban renewal from the perspective of improving thermal environment.
Science of The Total Environment, August 2022
Zhenyu Wang, Keyu Luo, Yuhao Zhao, Alex M. Lechner, Jiansheng Wu, Qingliang Zhu, Wei Sha, Yanglin Wang
Abstract: Long-term intensive open-pit mining can have huge impacts on ecosystems and the services they provide, affecting the integrity of ecosystem structures, functions and process and thus the “ecological security” of a whole mining region. The indirect and direct impacts of mining are spatially and temporally complex and therefore ecological security patterns need to be considered. However, to date there has been little research focusing on ecological security patterns in mining regions. This study aims to model and map ecological security and restoration priorities in an intensive open-cut coal mining region accounting for spatio-temporal changes of multiple ecosystem services. Four ecosystem services including habitat quality, carbon sequestration, water yield, and sediment retention were assessed and mapped in 1990, 2000, 2010, and 2020. Next ecological security patterns and restoration priorities were modelled and characterized using the Self-Organizing Feature Map to identify ecological sources, and circuit theory in Linkage Mapper to characterize connectivity and flows. The results showed that habitat quality, carbon sequestration, and water yield services were most affected by vegetation cover changes due to mining exploitation, while sediment retention was influenced by multiple natural factors, especially topography. Ecological sources, corridors, pinch-points and barriers showed various changing trends due to mined and built-up land expansion over time. Ecological source area declined from 1355.08km2 in 2000 to 584.92 km2 in 2020, while the number of corridors increased from 17 in 2000 to 25 in 2010 and then decreased to 21 in 2020. Although restoration has been conducted on some mine sites, regional-scale restoration needs greater consideration. This study provides decision-makers and stakeholders with a method for assessing regional-scale ecological security and restoration in a holistic and systematic way moving beyond a single mine, which is critical for balancing ecological security protection with minerals production in intensive mining regions.
Ecological Indicators, June 2022
Jian Peng, Huiling Lü, Ruilin Qiao, Shuying Yu, Zihan Xu, Jiansheng Wu,
Abstract: The Grain-for-Green Program (GFGP) in China, one of the largest payment fot ecosystem services (PES) programs, has been regarded as an effective approach to achieving sustainable development. However, empirical research on factors motivating GFGP participation willingness remains limited and the comparison of the influencing pathways under different compensation scenarios is lacked. In this case study of farm households’ willingness of participation in Mulan Paddock, China, based on a participatory rural appraisal with 11 sample towns and 438 valid questionnaires, the structural equation model was applied to identify key factors influencing participation in GFGP in Mulan Paddock before (2000) and after (2014) the program under different compensation scenarios (i.e. with or without subsidies). It was found that 84.28% of farm households had increased income after the implementation of the GFGP. When the government provided subsidies, the past program support would dominate the willingness to participate in the program. When the government did not provide subsidies, subjective perceptions about the ecological and economic benefits and awareness of landscape protection were further supplemented as the most important factors for household participation. Under the subsidized scenario, neighborhood behavior could enhance household participation in the GFGP, while the participation decision was negatively influenced without subsidies. The findings provide guidance for better implementation of the next round GFGPs in China, and also for investigating the correlation between PES and social welfare in other non-developed areas.
Atmospheric Pollution Research, May 2022
Keyu Luo, Zhenyu Wang, Jiansheng Wu
Abstract: Atmospheric pollution studies have linked diminished human activity during the COVID-19 pandemic to improve air quality. This study was conducted during January to March (2019–2021) in 332 cities in China to examine the association between population migration and air quality, and examined the role of three city attributes (pollution level, city scale, and lockdown status) in this effect. This study assessed six air pollutants, namely CO, NO2, O3, PM10, PM2.5, and SO2, and measured meteorological data, with-in city migration (WCM) index, and inter-city migration (ICM) index. A linear mixed-effects model with an autoregressive distributed lag model was fitted to estimate the effect of the percent change in migration on air pollution, adjusting for potential confounding factors. In summary, lower migration was associated with decreased air pollution (other than O3). Pollution change in susceptibility is more likely to occur in NO2 decrease and O3 increase, but unsusceptibility is more likely to occur in CO and SO2, to city attributes from low migration. Cities that are less air polluted and population-dense may benefit more from decreasing PM10 and PM2.5. The associations between population migration and air pollution were stronger in cities with stringent traffic restrictions than in cities with no lockdowns. Based on city attributes, an insignificant difference was observed between the effects of ICM and WCM on air pollution. Findings from this study may gain knowledge about the potential interaction between migration and city attributes, which may help decision-makers adopt air-quality policies with city-specific targets and paths to pursue similar air quality improvements for public health but at a much lower economic cost than lockdowns.
International Journal of Environmental Research and Public Health, May 2022
Jiansheng Wu, Xuechen Li, Si Li, Chang Liu, Tengyun Yi, Yuhao Zhao
Abstract: Research on urban thermal environments based on thermal comfort can help formulate effective measures to improve urban thermal and human settlement environments, which is of great significance for improving urban quality, urban climate change adaptation, and sustainable development. Taking 344 municipal administrative districts in China as study areas, the Universal Thermal Climate Index (UTCI) of each city in the last 20 years was calculated to evaluate thermal comfort. We then analyzed the thermal comfort and spatiotemporal heterogeneity of each city during a typical heat wave. Finally, the driving forces of the potential socioeconomic, natural, and landscape factors influencing thermal comfort were analyzed using geographic detectors. The results show that the thermal comfort index had similar spatial patterns and differentiation characteristics in different years, and the interannual variation was not obvious. Cities in the typical heat wave period were mainly distributed in East and Northwest China. The driving factor in the contribution rate of the same index in different years was basically the same and was not affected by the change in years, and the highest contribution rate was the natural factor.
Urban Forestry & Urban Greening, May 2022
Jiansheng Wu, Shengyong Zhang, Yuhang Luo, Hongliang Wang, Yuhao Zhao
Abstract: With the acceleration of urbanization, construction land is gradually expanding, leading to a loss of ecological land. This is increasing the risk of connectivity loss between important natural habitats. In this study, potential ecological corridors and stepping stones under ecological security patterns with different connectivity levels were identified according to the important habitats and resistance surfaces. We analyzed the development potential, vulnerability, and connectivity loss of a fragmented landscape using a support vector machine (SVM), a circuit theory model, and the “exposure-vulnerability-potential loss” framework. Four types of stepping stones that require protection were defined according to the risk structure and level. The results showed that there are 40 important habitats and 50 potential ecological corridors in the ecological security pattern. The SVM results indicated that the possibility of patch development is most sensitive to protection status (−0.923), followed by the slope (−0.770), and distance from the city (−0.210) and roads (−0.147). Additionally, the impact of railways (0.056) and night-time light (0.092) was limited. Elevation (0.267) had a positive effect on development. With an increased security level, the proportion of middle- and high-risk stepping stones gradually decreased, which means that the risk of connectivity loss under urban development can be reduced by creating a security pattern with a higher level and including more stepping-stone patches. Connectivity loss risk management can provide a reference for ecological control line revision and land use planning.
Remote Sensing, April 2022
Han Wang, Bingxin Li, Tengyun Yi, Jiansheng Wu
Abstract: Anthropogenic interferences through various intensive social-economic activities within construction land have induced and strengthened the Urban Heat Island (UHI) effects in global cities. Focused on the relative heat effect produced by different social-economic functions, this study established a general framework for functional construction land zones (FCLZs) mapping and investigated their heterogeneous contribution to the urban thermal environment, and then the thermal responses in FCLZs with 12 environmental indicators were analyzed. Taking Shenzhen as an example city, the results show that the total contribution and thermal effects within FCLZs are significantly different. Specifically, the FCLZs contribution to UHI regions highly exceeds the corresponding proportions of their area. The median warming capacity order of FCLZs is: Manufacture function (3.99 °C) > Warehousing and logistics function (3.69 °C) > Street and transportation function (3.61 °C) > Business services function (3.06 °C) > Administration and public services function (2.54 °C) > Green spaces and squares function (2.40 °C) > Residential function (2.21 °C). Both difference and consistency coexist in the responses of differential surface temperature (DST) to environmental indicators in FCLZs. The thermal responses of DST to biophysical and building indicators in groups of FCLZs are approximately consistent linear relationships with different intercepts, while the saturation effects shown in location and social-economic indicators indicate that distance and social-economic development control UHI effects in a non-linear way. This study could extend the understanding of urban thermal warming mechanisms and help to scientifically adjust environmental indicators in urban planning.
93. Study on Air Quality and Its Annual Fluctuation in China Based on Cluster Analysis
International Journal of Environmental Research and Public Health, April 2022
Shengyong Zhang , Yunhao Chen, Yudong Li, Xing Yi, Jiansheng Wu
Abstract: Exploring the spatial and temporal distribution characteristics of air quality has become an important topic for the harmonious development of human and nature. Based on the hourly data of CO, O3, NO2, SO2, PM2.5 and PM10 of 1427 air quality monitoring stations in China in 2016, this paper calculated the annual mean and annual standard deviation of six air quality indicators at each station to obtain 12 variables. Self-Organizing Maps (SOM) and K-means clustering algorithms were carried out based on MATLAB and SPSS Statistics, respectively. Kriging interpolation was used to get the clustering distribution of air quality and fluctuation in China, and Principal Component Analysis (PCA) was used to analyze the main factors affecting the clustering results. The results show that: (1) Most areas in China are low-value regions, while the high-value region is the smallest and more concentrated. Air quality in northern China is worse, and the annual fluctuations of the indicators are more dramatic. (2) Compared with AQI, AQFI has a strong indication significance for the comprehensive situation of air quality and its fluctuation. (3) The spatial distribution of SOM clustering results is more discriminative, while K-means clustering results have a large proportion of low-mean regions. (4) PM2.5, PM10 and CO are the main pollutants affecting air quality and fluctuation, followed by SO2, NO2 and O3.
BMC Public Health, February 2022
Huagui Guo, Xin Li, Jing Wei, Weifeng Li, Jiansheng Wu, Yanji Zhang
Abstract:
Background
Many studies have reported the effects of PM2.5 and PM10 on human health, however, it remains unclear whether particular matter with finer particle size has a greater effect.
Objectives
This work aims to examine the varying associations of the incidence rate of female lung cancer with PM1, PM2.5 and PM10 in 436 Chinese cancer registries between 2014 and 2016.
Methods
The effects of PM1, PM2.5 and PM10 were estimated through three regression models, respectively. Mode l only included particular matter, while Model 2 and Model 3 further controlled for time and location factors, and socioeconomic covariates, respectively. Moreover, two sensitivity analyses were performed to investigate the robustness of three particular matte effects. Then, we examined the modifying role of urban-rural division on the effects of PM1, PM2.5 and PM10, respectively.
Results
The change in the incidence rate of female lung cancer relative to its mean was 5.98% (95% CI: 3.40, 8.56%) for PM1, which was larger than the values of PM2.5 and PM10 at 3.75% (95% CI: 2.33, 5.17%) and 1.57% (95% CI: 0.73, 2.41%), respectively. The effects of three particular matters were not sensitive in the two sensitivity analyses. Moreover, urban-rural division positively modified the associations of the incidence rate of female lung cancer with PM1, PM2.5 and PM10.
Conclusions
The effect on the incidence rate of female lung cancer was greater for PM1, followed by PM2.5 and PM10. There were positive modifying roles of urban-rural division on the effects of three particular matters. The finding supports the argument that finer particular matters are more harmful to human health, and also highlights the great significance to develop guidelines for PM1 control and prevention in Chinese setting.
Remote Sensing, January 2022
Xuechen Li, Yuhang Luo, Jiansheng Wu
Abstract: Rapid urbanization has a significant impact on the ecological environment. Net primary productivity (NPP) can effectively reflect the growth of urban vegetation and the carbon sequestration capacity of an ecosystem. Taking the rapidly growing Pearl River Delta (PRD) as our study area, the relative contributions of human activities and climate change to NPP were analyzed using an improved two-step method based on residual trend analysis. The decoupling index was used to compare the coordinated development of socioeconomic factors and the NPP in different time periods. This study lays the foundation for formulating comprehensive and reasonable urban low-carbon development measures. The results showed that (1) NPP decreased significantly before 2010, but by 2019, NPP in most regions of the PRD showed a slight increase. The NPP of new urban land was better than that of original urban land. (2) The negative contribution of climatic factors to NPP was clearer than that of human activities, and human activities contributed positively to NPP outside urban land. (3) The decoupling status of socioeconomic factors and NPP is improving, and the degree of decoupling in 2010–2019 was higher than that in 2000–2010. In conclusion, as the first forest urban agglomeration in China, the PRD has shown a good implementation of carbon sequestration policies, which can provide a reference for the coordinated development of urbanization and carbon sequestration.
International Journal of Environmental Research and Public Health, February 2022
Jiansheng Wu, Jiayi Fu, Hongliang Wang, Yuhao Zhao, Tengyun Yi
Abstract: Previous Studies, such as the evaluation of the supply of and demand for regional medical resources and carrying capacity assessments, require further development. This paper aims to evaluate the carrying capacity and spatial distribution of medical resources in Shenzhen from the perspective of supply and demand, and to conduct a time-series variation of the coupling coordination degree from 1986 to 2019. The two-step floating catchment area method was employed to quantify the carrying capacity and coupling coordination degree method and spatial autocorrelation analysis were applied to analyze spatial distribution between supply and demand. The results were as follows. (1) The carrying capacity index in more than 50% of the districts was classified as low-grade. The percentage of regions with good grades was 8.27%. The regions with a high carrying capacity were distributed in the central and southeastern areas. (2) The coupling coordination continued to rise, increasing from 0.03397 in 1986 to 0.33627 in 2019. (3) The level of supply and demand for medical resources in Shenzhen increased from 1986 to 2019, and the highest degree of compatibility between the supply and the population size was largely concentrated in the western and eastern regions. This research can provide a theoretical reference for Shenzhen to rationally plan medical resources and improve the carrying capacity of medical resources.
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