Carbon dioxide mitigation co-effect analysis of clean air policies: lessons and perspectives in China's Beijing-Tianjin-Hebei region

In 2018, the Beijing-Tianjin-Hebei (BTH) area launched the Blue Sky Protection Campaign (BSPC) to control atmospheric pollution. CO2 emissions could be significantly reduced due to the co-effects of implementing the BSPC. This paper employs the Greenhouse Gas and Air Pollution Interactions and Synergies Asia model to quantitatively evaluate the CO2 reductions when implementing the BSPC in the BTH region. The results indicate that CO2 emissions can be reduced by 20.7 Mt (equivalently, a 19.7% reduction in the corresponding baseline scenario), 6.8 Mt (3.8%), and 80.2 Mt (9.2%) by 2020 for Beijing, Tianjin, and Hebei, respectively, as a co-benefit of the BSPC. By 2030, it is estimated that the CO2 emission reductions will be 37.8 Mt (26.6%), 4.85 Mt (2.5%), and 69.9 Mt (8.6%) for Beijing, Tianjin, and Hebei, respectively. NOx presents the highest co-effects with CO2 in each region. From the key sector perspective, sectors of power and heating in Beijing, residential combustion in Tianjin, and industrial combustion in Hebei are the most important sector that presents the highest co-effects on CO2 emission reductions due to the application of BSPC. We suggest that the implementation of BSPC, specifically the energy control measures in the power and heating, residential combustion, and industrial combustion sectors for Beijing, Tianjin, and Hebei, respectively, have high synergies and can simultaneously reduce CO2 and other atmospheric emissions. The results contribute to city-level policymaking on facilitating air pollution control and climate change mitigation among different governmental departments.