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Based on the panel data in Chinese provinces from 2000 to 2017, this paper first uses the parameterized quadratic function of the directional distance function to estimate carbon abatement costs of 30 provinces in China, and further studies its long-term evolutionary characteristics. Second, this paper studies the spatial distribution pattern of carbon abatement cost. The results show that the carbon abatement cost has increased as a whole during the study period. Moreover, the spatial distribution of carbon abatement costs in China shows a geographical clustering feature, and the positive spatial agglomeration is significant after 2008.

Fine particulate matter (PM 2.5 ) can damage airway epithelial barriers. The anion transport system plays a crucial role in airway epithelial barriers. However, the detrimental effect and mechanism of PM 2.5 on the anion transport system are still unclear. In this study, airway epithelial cells and ovalbumin (OVA)-induced asthmatic mice were used. In transwell model, the adenosine triphosphate (ATP)-induced transepithelial anion short-circuit current (I sc ) and airway surface liquid (ASL) significantly decreased after PM 2.5 exposure. In addition, PM 2.5 exposure decreased the expression levels of P2Y2R, CFTR and cytoplasmic free-calcium, but ATP can increase the expressions of these proteins. PM 2.5 exposure increased the levels of Th2-related cytokines of bronchoalveolar lavage fluid, lung inflammation, collagen deposition and hyperplasisa of goblet cells. Interestingly, the administration of ATP showed an inhibitory effect on lung inflammation induced by PM 2.5 . Together, our study reveals that PM 2.5 impairs the ATP-induced transepithelial anion I sc through downregulating P2Y2R/CFTR pathway, and this process may participate in aggravating airway hyperresponsiveness and airway inflammation. These findings may provide important insights on PM 2.5 -mediated airway epithelial injury., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)