Building Better Cities: Evaluating the Effect of Circular Economy City Construction on Air Quality via a Quasi-Natural Experiment.

The resource utilization of a circular economy should reflect both economic and environmental values. Resource utility can be measured by GDP in the short term, while environmental value is challenging to measure; that is, the improvement in air quality is not effectively evaluated. In order to examine this initiative, using China's pilot cities of circular economy as a quasi-natural experiment, we construct a difference-in-difference (DID) strategy for estimation. The results demonstrate the following: (1) the pollutant emissions of pilot cities decline by 2.92 percentage points (p < 0.01) compared to unpiloted cities, (2) the policies on pilot cities more rapidly enhanced air quality for central cities and those with a low level of economic development, and (3) pilot cities significantly enhance air quality by decreasing energy consumption per unit of GDP. We provide the first empirical evidence of the effectiveness of circular economy pilot cities in improving air quality.

Influencing Factors of CO2 Emissions in Chinese Power Industry: A Study from the Production and Consumption Perspectives.

China's huge regional differences are taken into consideration to study the influencing factors and their differences in CO2 emissions of the power industry from different regions. This study aimed to improve the efficiency of CO2 emission reduction policies. From the production and consumption perspectives, this study analyzes the influencing factors of CO2 emissions and utilizes the Logarithmic Mean Divisia Index (LMDI) to decompose CO2 emissions with consideration of the cross-regional power dispatching in the power industry. The results indicate that the trend of CO2 emissions in the eastern, central, and western China seems similar during years 2005 to 2017 no matter from which perspective. From the production perspective, power consumption is the main factor in CO2 emission increase and its affect extent may vary from different regions over a period of time. Energy efficiency inhibits CO2 emission increase in all regions. The power structure and power distribution across regions affect CO2 emissions significantly different in amount and direction from region to region. From the consumption perspective, economic activity plays a major role in CO2 emission increase and plays a similar role in the trend of CO2 emissions in three regions, but its affect extent on CO2 emissions varies in different regions. Targeted policy recommendations are provided to reduce CO2 emissions more effectively from China's power industry.

Comparison of clinical esthetic outcomes of immediately placed implants with and without immediate provisionalization in single-tooth implants of the esthetic area: A protocol for systematic review and meta-analysis.

BACKGROUND: Immediately placed implants with immediate provisionalization have become attractive options for patients and clinicians. However, there is no agreement on the esthetic advantages of immediately placed implants with immediate provisionalization. The aim of this systematic review and meta-analysis will be to assess the effect of immediate provisionalization on the clinical esthetic outcomes of immediately placed implants in a single-tooth implant of the esthetic area. METHODS: An electronic search of MEDLINE/PubMed, EMBASE, Web of Science, Clinicaltrials.org., Cochrane Library, China Biology Medicine (CBM), Wan Fang Database, China National Knowledge Infrastructure Database (CNKI), and VIP Science Technology Periodical Database will be performed. The search will be carried out in the databases for articles published until May 2021. Two researchers will independently perform the literature selection, data extraction and quality assessment. Only randomized controlled trials (RCTs) reporting on the impact of immediate provisionalization on the clinical esthetic outcomes of implants immediately placed in a single-tooth implant of the aesthetic area will be included. The primary outcome of this study will be the esthetic outcome assessed by the objective index and patient satisfaction. The survival rate of implants and restorations and the changes in mucosa and bone around implants will also be analyzed. The included studies will be analyzed by Review Manager 5.3, and a meta-analysis will be performed. RESULTS: The study will evaluate the clinical esthetic outcomes of immediately placed implants with and without immediate provisionalization in single-tooth implants of the esthetic area. The results will provide clinicians with a better treatment approach in their application. CONCLUSION: This systematic review and meta-analysis will provide more reliable, evidence-based data for the impact of immediate provisionalization on the clinical esthetic outcomes of immediately placed implants, which may or may not be beneficial. REGISTRATION NUMBER: PROSPERO registration number: CRD42021221669.

Spatial Effect of Industrial Energy Consumption Structure and Transportation on Haze Pollution in Beijing-Tianjin-Hebei Region.

Haze pollution has a serious impact on China's economic development and people's livelihood. We used data on PM2.5 concentration, industrial energy consumption structure, economic development and transportation in Beijing-Tianjin-Hebei and surrounding cities from 2000 to 2017, and analyzed the spatial effect of industrial energy consumption structure and traffic factors on haze pollution by using spatial autoregressive model (SAR) and spatial error model (SEM). The results indicated that: (1) The global spatial correlation analysis showed that haze pollution had a significant positive spatial correlation, and the local spatial correlation analysis showed that the high-high clusters of PM2.5 were located in the south and middle of the region; (2) The change of industrial energy consumption structure was highly correlated with haze pollution, namely, the increase of industrial energy consumption led to the deterioration of environmental quality; (3) The change of economic development was highly correlated with haze pollution. There was no clear EKC relationship between haze pollution and economic development in Beijing-Tianjin-Hebei region and surrounding cities. However, the relationship was similar to inverted U-shaped curve; (4) The change of traffic jam was highly correlated with haze pollution, namely, the increase of fuel consumption per unit road area led to the deterioration of environmental quality. Based on the above results, from the perspective of space, the long-term measures for haze control in Beijing-Tianjin-Hebei and surrounding cities can be explored from the aspects of energy conservation and emission reduction, industrial transfer, vehicle emission control, traffic restrictions and purchase restrictions.