[Carbon Dioxide Mitigation Co-effect Analysis of Structural Adjustment Measures in the "2+26" Cities in the Jing-Jin-Ji Region and Its Surroundings].

The Three-Year Action Plan for Winning the Blue Sky Defense Battle states that structural adjustments of industrial, energy, transportation, and land use are important to significantly reduce CO and air pollutant emissions. This co-effect is evident but has not been quantified at the city-cluster level. This study developed an emission inventory for the "2+26" cities of the Jing-Jin-Ji region and its surroundings and quantitatively analyzed the impacts of measures in the Three-Year Action Plan for Winning the Blue Sky Defense Battle on the emissions of CO and major air pollutants using Greenhouse Gas and Air Pollution Interactions and Synergies in the "2+26" cities model (GAINS-JJJ). The results showed that in the "2+26" cities, the emission reductions in CO, primary PM, SO, NO, and NH under policy scenario 2020 were 29.1 Mt (equivalent to 2% of the emissions in 2017), 203.8 (21%), 281.8 (27%), 485.5 (17%), and 34.3 kt (3%), respectively, relative to 2017. In terms of the cities or sectors, the higher the pollutant emissions, the higher the reduction achieved. The CO mitigation co-effect results showed that industrial adjustment measures, such as eliminating backward production capacity, upgrades on industrial boilers, and phasing out small and polluting factories, contributed the most to the co-effect of CO emission reduction, whereas NO presented the highest co-effects, with CO among the different air pollutants.