With the rapid economic growth and development, the problem of environmental pollution in China’s cities is becoming increasingly serious, and environmental pollution takes on a regional difference. There is, however, little comprehensive evaluation on the environmental performance and the regional difference of strictly-environmental-monitored cities in China. In this paper, the environmental performance of 109 strictly-environmental-monitored cities in China is evaluated in terms of natural performance, management performance, and scale performance by Data Envelopment Analysis (DEA), incorporating PM_2.5 and PM₁₀ as undesirable outputs. The empirical results show that: (1) At present, the natural performance is quite high, while the management performance is noticeably low for most cities. (2) The gap between the level of economic development and environmental protection among cities in China is large, and the scale efficiency of big cities is better than that of smaller cities. The efficiency value of large-scale cities such as Beijing, Shanghai, Guangzhou, Shenzhen, etc. is high, equaling 1; the value of smaller cities such as Sanmenxia, Baoding, Mudanjiang, and Pingdingshan is low, close to 0, indicating that big cities are characterized by high environmental efficiency. (3) From the perspective of region, the level of environmental performance in China is very uneven. For example, the environmental efficiency level of the Pan-Pearl River Delta region is superior to that of the Pan-Yangtze River region and the Bahia Rim region, whose values of environmental efficiency are 0.858, 0.658, and 0.622 respectively. The average efficiency of the Southern Coastal Economic Zone, Eastern Coastal Comprehensive Economic Zone, and the Comprehensive Economic Zone in the middle reaches of the Yangtze River is higher than that of other regions. Finally, corresponding countermeasures and suggestions are put forward. The method used in this paper is applicable to the performance evaluation of cities, and the results of the evaluation reflect the differences of the environmental performance level between strictly-environmental-monitored cities and different regions in China, providing reference for the balanced environmental development of cities and regions.

The manufacturing industry is an important part of the national industrial system, and is usually an industry with high carbon content. However, few studies have been carried out on the total amount, structure and the trend of the embodied carbon emission in the international trade of the Chinese manufacturing industry. Based on the input–output method, the thesis proposes the coefficient of direct carbon emission and complete carbon emission and a method for calculating the embodied carbon of the export trade. It also calculates the coefficient of direct carbon emission and complete carbon emission for the Chinese manufacturing sector from 2000 to 2015 and breaks down the embodied carbon change of export trade in the manufacturing industry to a technological effect, structural effect and scale effect by using the method of structural decomposition. Several inspiring conclusions could be drawn from the thesis. For example: (1) the coefficient of both the direct carbon emission and the complete carbon emission has been decreasing significantly, indicating the achievements of the energy saving and emission reduction of the Chinese manufacturing industry. (2) The embodied carbon emission from the manufacturing exports remains high and presents a rising tendency. The main sectors that export the embodied carbon includes “S10 mechanical equipment and instruments”, “S9 metal products”, “S6 chemical industry”, etc., which should be the key sectors on reducing embodied carbon in exports. (3) The driving force of the embodied carbon exports lies in the scale effect of the manufacturing industry, on which the technical effect of the industry has a significant negative effect. The structural effect should have a positive influence that takes on a rising tendency; generally, this effect is only two-thirds of the scale effect. Finally, the corresponding policy suggestions have been made.

Being the biggest developing nation in the world, China's huge energy consumption, widely distributed carbon emission problems, and complex and variable air pollution situation have always been topics that have attracted great attention from the academic community.The goal of this research is to fully examine whether China's recent implementation of carbon emissions trading has aided in the combined reduction of CO2 and PM2.5. The actual effects of carbon emissions trading policies in terms of environmental improvement and carbon emission reduction are examined by using the double-difference method and intermediary effect modeling. Panel data from 284 Chinese cities at the prefecture level from 2000 to 2019 are used, along with the seven carbon emissions trading pilot events that were fully launched in 2014 as a quasi-natural experiment.The analysis demonstrates that: (1) carbon emissions trading effectively realizes the joint reduction of CO2 and PM2.5; (2) the carbon trading policy has a more pronounced effect on reducing pollution and emissions in both the central and western regions, but does not lower carbon emissions in the eastern region, according to the results of the heterogeneity study; (3) The intermediary mechanism of carbon emissions trading to promote pollution reduction and carbon reduction is the significant mediating effect of energy consumption intensity on carbon dioxide and PM2.5. This paper enriches the research literature on carbon market and air pollutant emission reduction, and the empirical conclusions obtained are favourable for China and other similar countries and regions to carry out practical activities to reduce pollution and carbon emissions.