Sichuan Chongqing Research Articles

The Abrupt Change in Potential Evapotranspiration and Its Climatic Attribution over the Past 50 Years in the Sichuan–Chongqing Region, China

The Abrupt Change in Potential Evapotranspiration and Its Climatic Attribution over the Past 50 Years in the Sichuan–Chongqing Region, China

Establishing resilience-targeted prediction models of rainfall for transportation infrastructures for three demonstration regions in China

Rainstorm is one of the global meteorological disasters that threaten the safety of transportation infrastructure and the connectivity of transportation system. Aiming to support the resilience assessment of transportation infrastructure in three representative regions: Sichuan–Chongqing, Yangtze River Delta, and Beijing-Tianjin-Hebei-Shandong, rainfall data over 40 years in the three regions are collected, and the temporal distribution of rainfall are analyzed. Prediction equations of rainfall are established. For the purpose of this, the probabilistic density function (PDF) is assigned to the rainfall by fitting the frequency distribution histogram. Using the assigned PDF, the rainfall data are transformed into standard normal space where regression of prediction equations is performed and the prediction accuracy is tested. The results show that: (1) The frequency of rainfall in the three regions follows a lognormal distribution based on which the prediction equations of rainfall can be established in standard normal space. The error of regression shows no remarkable dependence on self-variables, and the significance analysis indicates that the equations proposed in this paper are plausible for predicting rainfalls for the three regions. (2) The Yangtze River Delta region has a higher risk of rainstorm disaster compared to the other two regions according to the frequency of rainfall and the return period of precipitation concentration. (3) Over the period of 1980–2021, the Sichuan–Chongqing region witnessed an increase in yearly rainfall but a decrease in rainstorm disasters, whereas the other two regions experienced a consistent rise in both metrics.

Study on the Parallel Competition Governance Model of Multiple Subjects in the "Unveiling of the List of Commanders"

Study on the Parallel Competition Governance Model of Multiple Subjects in the "Unveiling of the List of Commanders"

Ecological Security Patterns Research Based on Ecosystem Services and Circuit Theory in Southwest China

The rapid economic development in the Chengdu–Chongqing Economic Circle (CCEC) has exerted significant pressure on the ecological environment of the Sichuan–Chongqing Region in China. Balancing ecological protection and economic development has become an imperative challenge that needs to be addressed. In this study, we employed land use/cover data and environmental threat factors to construct Ecological Security Patterns (ESPs) for the CCEC using the InVEST model and Circuit Theory. The research findings revealed the following key outcomes: (1) The total area of suitable habitat in the CCEC was 208,728.3 km2, accounting for 87.14% of the study area. Habitat quality exhibited regional variations, with higher quality habitats predominantly found in the western and northeastern parts, and lower quality habitats in the central region. (2) The CCEC consisted of areas with low, medium, high, and optimal habitat quality, spanning 140,912.18 km2, 15,341.89 km2, 15,578.38 km2, and 36,895.85 km2, respectively. These areas accounted for 58.83%, 6.40%, 6.50%, and 15.40% of the study area, respectively. (3) The ESPs in the CCEC encompassed 22 ecological nodes, 36 clusters of ecological corridors, and 136 ecological sources. Ecological corridors served as radial connections, linking each ecological node and ecological source along mountain ranges, forested areas, river networks, and valleys. (4) The core ecological regions forming the ESPs of the CCEC included the Qionglai–Minshan–Longquan Mountains in the west, Tiefeng–Fangdou–Qiyue–Wushan Mountains in the east and northeast, and Dalou Mountain in the southeast. These regional-scale findings provide valuable insights for policymakers to implement targeted measures for ecological protection and promote green development. They offer objective guidance and constraints for managing urban expansion and anthropogenic activities, ultimately enhancing the ecological security level of the CCEC.

Analysis of a Multiple Traffic Flow Network’s Spatial Organization Pattern Recognition Based on a Network Map

Detecting the spatial organization patterns of urban networks with multiple traffic flows from the perspective of complex networks and traffic behavior will help to optimize the urban spatial structure and thereby promote the sustainable development of the city. However, there are notable differences in regional spatial patterns among the different modes of transportation. Based on the road, railway, and air frequency data, this article investigates the spatial distribution and accessibility patterns of multiple transportation flows in the Yangtze River Economic Belt. Next, we use the TCD (Transportation Cluster Detection) community discovery algorithm and integrate it with the Baidu Maps API to obtain real-time time cost data to construct a community detection model of a multiple traffic flow network. We integrate the geographical network and topological network to perform feature extraction and rule mining on the spatial organization model of the urban network in the Yangtze River Economic Belt. The results show that: (1) The multiple traffic flow network of the Yangtze River Economic Belt has significant spatial differentiation. The spatial differentiation of aviation and railway networks is mainly concentrated between regions and within provinces, while the imbalance of highway networks is manifested as an imbalance within regions and between provinces. (2) The accessibility pattern of the highway network in the Yangtze River Economic Belt presents a “core–edge” spatial pattern. The accessibility pattern of the railway network generally presents a spatial pattern of “strong in the east and weak in the west”. Compared with sparse road and railway networks, the accessibility pattern of the aviation network shows a spatial pattern of “time and space compression in western cities”. (3) A total of 24 communities were identified through the TCD algorithm, mainly encompassing six major “urban economic communities” located in Guizhou, Yunnan, Anhui, Sichuan–Chongqing, Hubei–Hunan–Jiangxi, and Jiangsu–Zhejiang–Shanghai. (4) The urban network space organization model of the Yangtze River Economic Belt can be roughly divided into three models: the “single-core” model, with Guizhou, Kunming, and Hefei as the core, the “dual-core” model, constructed by Chengdu–Chongqing, and the “multi-core” model, constructed by Changsha–Wuhan–Nanchang and Shanghai–Nanjing–Hangzhou. This model of urban network spatial organization holds indicative significance in revealing the spatial correlation pattern among prefecture-level city units.

Exploring the factors and spatial patterns of national night cultural tourism consumption agglomeration zones in China

This study is based on the theory of spatial structure and uses the geographic information system's (GISs) spatial analysis technology to investigate the spatial distribution characteristics and influencing factors of 243 national night cultural and tourism consumption agglomeration zones (NNCTCAZs) in China. Furthermore, this study employs various analytical methods, including the nearest index, geographic concentration index, imbalance index, nuclear density analysis, buffer analysis and geographic detector method. The results reveal that NNCTCAZs exhibit an imbalanced spatial distribution, with a predominant concentration in the east and southwest regions of China. Furthermore, the ‘core-edge’ structure of this distribution is discernible. The spatial distribution density of NNCTCAZs is uneven, with high-density areas primarily located in the Yangtze River Delta, Pearl River Delta and Sichuan–Chongqing regions. This distribution pattern exhibits the characteristics of being progressive, that is, strong in the east and west and having small agglomerations with large dispersion. In addition, these areas are mainly concentrated in the central regions of cities and the surrounding areas of popular tourist attractions. The spatial layout of NNCTCAZs is mainly influenced by the level of social development, the tourism industry and regional gross domestic product (GDP), which are considered the core determinants. Furthermore, the development level of traffic conditions plays a crucial role in shaping the spatial layout, whereas the impact of the cultural environment and economic conditions is comparatively less pronounced.

Spatiotemporal variation characteristics analysis of infrastructure iron stock in China based on nighttime light data

Abstract Iron is one of the most important basic materials in infrastructure development, spatial and temporal variation characteristics analysis of infrastructure iron stocks is conducive to revealing its distribution and change patterns from different scales, which can provide a scientific basis for sustainable urban development and iron resource management in China. In this article, we first calculated provincial infrastructure iron stock data from 2000 to 2020. Then, fitting equations between nighttime lighting data and infrastructure iron stock are constructed to simulate the spatial distribution of China’s infrastructure iron stock at 500 m resolution from 2000 to 2020. Finally, the spatial and temporal dynamics of China’s infrastructure iron stock is analyzed from four scales: national, regional, provincial, and urban agglomeration. The results show as follows: (1) China’s infrastructure iron stock grew at an average annual rate of 26.42% from 2000 to 2020, with China’s infrastructure iron stock increasing 6.28 times over the 21 years. Construction facilities are the most important part of the infrastructure iron stock, and its share is still increasing. (2) On a regional scale, the high-growth type of infrastructure iron stock is mainly distributed in the eastern region, while the no-obvious-growth type is mainly distributed in the western region. The high grade of infrastructure iron stock is mainly distributed in the eastern region, while the low grade is mainly distributed in the western region. (3) On a provincial scale, the highest share of no-obvious-growth type of infrastructure iron stock is in Xinjiang. The highest proportion of infrastructure iron stock of high-growth type is in Jiangsu. The highest proportion of low-grade infrastructure iron stock is in Xinjiang. The highest proportion of infrastructure iron stock of high grade is in Beijing. (4) In terms of urban agglomerations, the high-growth type of infrastructure iron stock is mainly located in Shanghai–Nanjing–Hangzhou, while the no-obvious-growth type is mainly located in the Middle south of Liaoning. The high-grade infrastructure iron stock is mainly distributed in Shanghai–Nanjing–Hangzhou, while the low grade is mainly distributed in Sichuan–Chongqing.

Has Rural Public Services Weakened Population Migration in the Sichuan–Chongqing Region? Spatiotemporal Association Patterns and Their Influencing Factors

The association between rural public services (RPSs) and population migration (PM) has become a key aspect of rapid urbanization in developing countries and an important breakthrough for improving rural–urban relations. An in-depth analysis of the heterogeneity of the weakening effect of RPSs on PM at different transformation phases and the internal mechanism of the evolution of association patterns driven by RPSs and PM helps to ensure better co-ordinated urban and rural development. This paper establishes an interactive analysis framework for measuring the spatiotemporal association and regional differences between RPSs and PM in the Sichuan–Chongqing region (SCR), and reveals the influence mechanism by employing multiscale geographically weighted regression (MGWR). The results indicate that the association rapidly increased with clear spatial heterogeneity across topographic units and the weakening effect of RPSs on PM begin to diverge during the urban–rural transition. The natural, economic, social, and urban–rural disparity factors in terms of the association exhibit significant spatial variability. In mountainous areas, where topography dominates, RPSs fail to effectively weaken rural migration. However, in the plain areas, urbanization is the main driver of urban–rural transition, and the adaptive upgrading and transformation of RPSs has made their weakening effect stronger, thus alleviating rural exodus and increasing population concentration. All these findings show that differentiated optimization strategies adhering to the association trends should be proposed for a deeper integration of rural revitalization and new urbanization in the SCR.

Research into the Spatiotemporal Characteristics and Influencing Factors of Technological Innovation in China’s Natural Gas Industry from the Perspective of Energy Transition

Promoting technological innovation in the natural gas industry is a feasible means of achieving energy transition. Guided by the geographic innovation theory, this article carries out research on the scale, technical fields, capabilities, and influencing factors of technological innovation in the natural gas industry of 312 Chinese prefecture-level cities, making use of the cusp catastrophe model, the center of gravity and standard deviational ellipse, exploratory spatial data analysis, and geographically and temporally weighted regression (GTWR). The research shows the following: (1) Technological innovation in China’s natural gas industry has continuously expanded in terms of scale, with the number of participating cities increasing, showing a spatially uneven pattern of local agglomeration and national diffusion. (2) There have been significant innovation achievements in natural gas equipment and engineering, but natural gas utilization is lagging in comparison, with drilling, new materials, environmental protection, pipe network engineering, and digital services becoming frontier fields, and collaborative innovation with the thermoelectric, metalworking, automotive, and other related industries having been initially established. (3) The unevenness of technological innovation capabilities is obvious, with the core advantages of Beijing–Tianjin being continuously strengthened and Sichuan–Chongqing, the Yangtze River Delta, the Pearl River Delta, Shandong Peninsula, and Liaodong Peninsula forming high-level technological innovation capability agglomerations. (4) The spatiotemporal pattern of technological innovation capability is the result of multiple factors, with northeastern cities mainly being affected by natural gas demands, northwestern cities being highly sensitive to capital strength, eastern cities mostly relying on urban development, and cities in North China mainly being bolstered by the strength of talent. (5) It is necessary to carry out further multi-agent and multi-scale future research on technological innovation in the natural gas industry and its relationship with the energy transition and to explore the interactivity of the influencing factors. This study may provide strategies for technological innovation in the natural gas industry from the perspective of the energy transition.

Research on the Coupling and Coordinated Development of the Tourism Industry and Regional Economy in the Economic Circle of the Sichuan–Chongqing Region in Southwest China

The construction of the Sichuan–Chongqing double-city economic circle represents a critical measure for high-quality development in China. The coordinated development of industry and economy is conducive to high-quality regional economic growth and the construction of a high-standard market system. This study selects 19 data indexes of the tourism industry and regional economy in the Sichuan–Chongqing region from 2000 to 2020 and analyzes the coupling coordination degree of them through a coupling coordination model. Such being the case, the gray correlation analysis method is used to explore the key factors affecting the coupling difference. It is found that the comprehensive development index of the tourism industry system and regional economic system of the Sichuan–Chongqing region witnesses a steady growth, but the overall performance of the regional economic system lags behind that of the tourism industry system. From the perspective of coupling coordination degree, the coupling coordination between the tourism industry and regional economy in the Sichuan–Chongqing region is increasingly strengthened, with the whole system being in the stage of running-in and high-level coupling. It has achieved the leap from unbalanced development to well-coordinated development. From the perspective of gray correlation analysis, the per capita consumption level of residents and regional GDP are the key factors affecting the coupling and coordination differences of the Sichuan–Chongqing circle.

Discussion on the Construction Plan of Photovoltaic Power Generation System for Oil and Gas Stations in Sichuan Chongqing Region

Discussion on the Construction Plan of Photovoltaic Power Generation System for Oil and Gas Stations in Sichuan Chongqing Region

The "Pollution Halo" Effect of FDI: Evidence from the Chinese Sichuan-Chongqing Urban Agglomeration.

In this paper, panel data from nineteen key cities in the Sichuan–Chongqing urban agglomeration from 2003 to 2016 were used as the study sample. Using the stochastic impacts by regression on population, affluence, and technology (STIRPAT) model, the effect of foreign direct investment (FDI) on particulate matter (PM2.5) pollution and its action mechanism in the Sichuan–Chongqing urban agglomeration were considered for both socioeconomic and natural factors. The results showed that the “pollution halo” hypothesis of FDI in the Sichuan–Chongqing urban agglomeration has been supported. There are significant positive spatial spillover effects of PM2.5 pollution in this urban agglomeration, and the introduction of FDI is conducive to alleviating PM2.5 pollution in the urban agglomeration. Similar to the “inverted U” curve proposed by the environmental Kuznets curve (EKC) hypothesis, there was a significant “inverted U” curve relationship between PM2.5 pollution and economic growth in the Sichuan–Chongqing urban agglomeration. However, there was a significant “U”-type curve relationship between the urbanization degree and the PM2.5 concentration, which indicates that the current urbanization mode may aggravate the pollution degree of PM2.5 in the urban agglomeration in the long term. Furthermore, the two natural factors of annual average temperature and annual precipitation play an important role in PM2.5 pollution and spatial spillover effect in the Sichuan–Chongqing urban agglomeration. Economic development and rationalization of the industrial structure are the main ways by which FDI affects PM2.5 pollution in the urban agglomeration. The research conclusions of this study can be of great practical significance to optimize the regional industrial layout, control PM2.5 pollution, and establish a sustainable development policy system in the Sichuan–Chongqing urban agglomeration.

Relationships Between Rapid Urbanization and Extreme Summer Precipitation Over the Sichuan–Chongqing Area of China

China has undergone rapid urbanization over the past few decades, and accordingly, changes have occurred in the extreme precipitation events. However, few studies have focused on the relationships between rapid urbanization and extreme precipitation events in southwest China, particularly in the Sichuan–Chongqing area, which has a complex topography and has experienced rapid urbanization over the past few decades. This is the first study to analyze the impact of urbanization on the amount, frequency, and intensity of extreme summer (June–August) precipitation events over the past 30 years. Our results indicate that extreme precipitation events primarily occurred in the urban-dominated Sichuan basin, particularly during the fast urbanization development stage (FUDS) of 1994–2015. Extreme precipitation amounts and intensities increased during the FUDS, implying the greater probability of individual precipitation events developing into heavy or extreme events in a particular area. In addition, the probability distribution functions of the occurrence and volume of strong convective events significantly increased during the FUDS. Finally, the annual increase in urban-scale land surface air temperature, increase in wet convection, and changes in wind speed are identified as essential factors leading to extreme precipitation events in this region.

Impacts of meteorological parameters on the occurrence of air pollution episodes in the Sichuan basin

Episodes of fine-particulate matter (PM2.5) pollution are a widespread and common occurrence in China, and have potentially serious implications for human health. Meteorological conditions play an important role in air quality and influence the formation of regional air pollution episodes. This study applied a new classification method and daily PM2.5 concentration data to (a) evaluate different levels of air pollution in the Sichuan–Chongqing region between 2015 and 2017, and (b) investigate their relationships with meteorological parameters including atmospheric boundary layer height, wind speed, temperature inversion, weather type, and atmospheric transport. We identified a total of 40 air pollution episodes, the most severe of which occurred in winter when the atmospheric layer height was low. These heavy pollution events also coincided with low surface (10 m) wind speeds and temperature inversions, weather conditions that generally result from low pressure over the northwestern Sichuan Basin (90–102° E, 28–36° N) and southerly atmospheric transport.

Exploring the effect of urban sprawl on carbon dioxide emissions: An urban sprawl model analysis from remotely sensed nighttime light data

The easily and effectively exploration of the effect of urban sprawl on carbon dioxide emissions (EUC) is highly important for developing a sustainable urban spatial structure and a low-carbon urban planning system in a country. However, the comprehensive understanding of EUC and its transmission factors remain inadequate because previous studies were mainly concentrated on a single city, stage, and region based on the statistical data and traditional optical remotely sensed images. Thus, taking 41 typical cities in Southwest China as examples, an urban sprawl (US) model was developed for quantifying US from remotely sensed nighttime light data. The degree of EUC were then verified in different city sizes, stages, and regions. The transmission factors of EUC were further evaluated. Results show that US can aggravate carbon dioxide emissions (CE), and the robust analysis further confirms the positive effect of US on CE. US in small cities has the strongest effect on CE, whereas that in medium cities has the weakest effect. In addition, EUC is greater in pre-stage (2000–2009) than that in post-stage (2010–2018). EUC in Guizhou, Yunnan, and Sichuan–Chongqing gradually decreases. The transmission factor results indicate that US can aggravate CE through the urban transport, construction industry, and urban heat island. It is suggested that more attention should be paid to US environmental problems with China's future urban development.

Prevalence of post-traumatic stress disorders and associated factors one month after the outbreak of the COVID-19 among the public in southwestern China: a cross-sectional study

BackgroundThe Coronavirus Disease 2019 (COVID-19) pandemic has rapidly spread across the whole world and brought strong psychological impact. This study aimed to evaluate the prevalence of post-traumatic stress disorders (PTSD) in the general people of southwestern China and associated factors 1 month after the outbreak of the COVID-19.MethodsThis study was started on 4–10 Feb 2020 based on online survey. The present work was carried out in the provinces of southeastern China, including Sichuan Province, Guizhou Province, Yunnan Province, and Chongqing City.1593 respondents aged 18 years and above administered to this study. Data on whether they have experienced confirmed or suspected COVID-19 of themselves/family members/acquaintances were also collected, and based on ‘yes’ answers, the number of affected individuals (via COVID-19) were categorized into four exposure levels i.e., non-affected, less, moderately, or significantly affected. The civilian version of the PTSD checklist and the self-reported information about COVID-19 were used.ResultsThe prevalence of PTSD was approximately 25.2%(n = 401/1593). The chances of developing PTSD were 6.053(OR = 6.053, 95% CI 1.394 to 26.280) or 3.673(OR = 3.673, 95% CI 1.738 to 7.765) times higher among respondents who had been significantly and moderately affected than those who had not been affected, accordingly. Male (OR = 1.484, 95% CI 1.147 to 1.920),younger age individuals (40 ~ 49 age group/<30 age group, OR = 0.395, 95% CI 0.258 to 0.606) and health care workers (OR = 1.788, 95% CI 1.155 to 2.277) were at higher risk of developing PTSD.ConclusionOur findings highlight that a positive correlation between the pandemic and PTSD. It is urgent to establish a screening and prevention systems for the population who are significantly exposed to COVID-19,and provide different psychological intervention strategies for different groups.

Influence of farmland marginalization in mountainous and hilly areas on land use changes at the county level

Agricultural works alter earth's surface at the largest scale among human-driven activities. Previous studies have focused more on the reclamation of natural land, however, farmland marginalization (FM), emerging as an important mean of land use changes in mountainous and hilly areas (MHAs) has always been overlooked in the background of production efficiency improvement along with urbanization and population migration. This paper examined the characteristics of the spatial-temporal distribution and conversion of marginalized farmland in the MHAs of China at county level (excluding Hong Kong, Macau, and Taiwan) from 1990 to 2020, regarding farmland in MHAs converted into non-built-up land as FM. The results showed that: (1) The total area of marginalized farmland in the MHAs was 1.03 × 106 km2. The counties with larger area of marginalized farmland were concentrated around the Hu Line, and those with higher ratio were distributed in southern mountainous areas. (2) The area of marginalized farmland in each stage exhibited a fluctuating trend from 1990 to 2020. Forests and grasslands were prioritized as the desirable types in land conversion, and had prominent spatial agglomeration. (3) The influence of FM in MHAs on land use changes at county level demonstrated significant spatial-temporal heterogeneity, with wide range and low intensity from 1990 to 2000 and 2015 to 2020, and narrow range and high intensity from 2000 to 2015, and the counties with high intensity were distributed in the Loess Plateau and Sichuan–Chongqing hilly region. (4) The slope of marginalized farmland exhibited a prominent rule of spatial distribution, but an insignificant temporal trend under the influence of governmental policies. The larger the slope was, the higher the degree of marginalization was, but not necessarily earlier it occurred. The results can provide a reference for the formulation and implementation of farmland protection policies.

A gridded emission inventory of semi-volatile and intermediate volatility organic compounds in China

An emission inventory of precursors is a prerequisite for the simulation of secondary organic aerosol (SOA), which could provide valuable information on the evolution of precursors, formation of SOA, and its influence on fine particle (PM2.5) abundance, oxidative capacity, and climate change. However, an emission inventory of semi-volatile and intermediate volatility organic compounds (S/IVOCs), the key precursor of SOA, particularly the gridded inventory that is appropriate for input into regional air quality models, remains limited in China, leading to an incomplete understanding of S/IVOCs sources and roles in SOA formation and the atmospheric environment. Therefore, a gridded emission inventory of S/IVOCs in China for 2016 was developed based on ample source-specific measured data on emission ratios of S/IVOCs to primary organic aerosols (POA) from literatures. The total emission of S/IVOCs was estimated to be 9.6 Tg, and industry and residential sectors were major sources of S/IVOCs, with contributions of 48.0% and 30.2%, respectively. The spatial variations suggested that S/IVOC emissions were mainly distributed in the highly industrialized and urbanized regions in China, such as Beijing–Tianjin–Hebei (BTH), the Yangtze River Delta (YRD), the Pearl River Delta (PRD), and the Sichuan–Chongqing (SC) regions, though the contributions and temporal patterns varied between different regions. Furthermore, uncertainty of the emission inventory was estimated to be within the range of −66%–153%, which was mainly attributed to emission ratios of IVOCs/POA for industry, transportation, and power plants. The gridded emission inventory developed in this study can be used to estimate the emissions of S/IVOCs in different regions, and can be applied to different models for a better understanding of the environmental effects of S/IVOCs.

Estimating Ground-Level Particulate Matter in Five Regions of China Using Aerosol Optical Depth

Aerosol optical depth (AOD) has been widely used to estimate near-surface particulate matter (PM). In this study, ground-measured data from the Campaign on Atmospheric Aerosol Research network of China (CARE-China) and the Aerosol Robotic Network (AERONET) were used to evaluate the accuracy of Visible Infrared Imaging Radiometer Suite (VIIRS) AOD data for different aerosol types. These four aerosol types were from dust, smoke, urban, and uncertain and a fifth “type” was included for unclassified (i.e., total) aerosols. The correlation for dust aerosol was the worst (R2 = 0.15), whereas the correlations for smoke and urban types were better (R2 values of 0.69 and 0.55, respectively). The mixed-effects model was used to estimate the PM2.5 concentrations in Beijing–Tianjin–Hebei (BTH), Sichuan–Chongqing (SC), the Pearl River Delta (PRD), the Yangtze River Delta (YRD), and the Middle Yangtze River (MYR) using the classified aerosol type and unclassified aerosol type methods. The results suggest that the cross validation (CV) of different aerosol types has higher correlation coefficients than that of the unclassified aerosol type. For example, the R2 values for dust, smoke, urban, uncertain, and unclassified aerosol types BTH were 0.76, 0.85, 0.82, 0.82, and 0.78, respectively. Compared with the daily PM2.5 concentrations, the air quality levels estimated using the classified aerosol type method were consistent with ground-measured PM2.5, and the relative error was low (most RE was within ±20%). The classified aerosol type method improved the accuracy of the PM2.5 estimation compared to the unclassified method, although there was an overestimation or underestimation in some regions. The seasonal distribution of PM2.5 was analyzed and the PM2.5 concentrations were high during winter, low during summer, and moderate during spring and autumn. Spatially, the higher PM2.5 concentrations were predominantly distributed in areas of human activity and industrial areas.

Determining the factors driving energy demand in the Sichuan-Chongqing region: an examination based on DEA-Malmquist approach and spatial characteristics.

Since the "China Western Development" plan was initiated in 2000, the Sichuan-Chongqing region has experienced rapid economic growth, especially in the energy segment. However, energy shortage and environmental degradation currently pose a significant hurdle for sustainable development in this region. In the existing literature on factors driving the energy demand, the effect of technological progress on energy demand is discussed as a whole, but few papers have investigated the effect of technological progress from the perspective of its components. Additionally, existing studies have neglected the temporal and spatial aspect of energy demand, thereby generating biased and unreasonable results. Correspondingly, in the current study, the factors driving the per capita energy demand in the Sichuan-Chongqing region over the 2005-2016 period were, to the best of our knowledge, explored for the first time by employing the data envelopment analysis-Malmquist method and spatial dynamic panel model concurrently. The empirical results suggest that an improvement in total factor productivity (TFP) plays a positive but insignificant role in decreasing energy demand. Additionally, there is clear evidence that the effect of TFP on energy demand primarily emerges through spatial spillover effects and their components.