Reduced rural residential emissions in the Northern China Plain from 2015 to 2021

China's rapid economic growth over the past few decades has been fueled by the fossil-fuel dominated energy system. In Northern China, coal and biomass are important fuel types for household cooking and heating. The use of coal and biomass not only contributes to CO₂ emissions, but also worsens the ambient air quality and further causes adverse health outcomes. Since 2016, action plans have been implemented annually to promote the substitution of solid fuel use in the rural households of the Beijing-Tianjin-Hebei and surrounding region ("2 + 26" region). However, a comprehensive evaluation of the emission reductions by the control policies is still lacking. In this study, we built a rural residential emission inventory in the "2 + 26" region based on two-phase national household surveys in 2010 and 2015. We evaluated the air pollutant and CO₂ reduction benefits of various control measures from 2015 to 2021 and discussed the opportunities for the synergistical control of air pollutant and CO₂ emissions. We estimated that, in 2015, the coal and biomass fuel consumption from rural households in the "2 + 26" region was 28.7 Mt. and 30.6 Mt., respectively, which resulted in 93.8 Mt., 416.5kt, 402.5kt, 80.1kt, 268.0kt, and 6122.2kt of CO₂, PM_2.5, SO₂, NO_x, VOCs, and CO emissions. With the implementation of household solid fuel substitution policies, air pollutant emissions were estimated to decrease by 53- 74 % from 2015 to 2021, while the percentage reduction of CO₂ was only 39 % due to additional emissions from the alternative clean energy sources. If biomass was treated as carbon-neutral fuel, the CO₂ reducing potential was even lower. Building a clean and sustainable rural energy system is a multi-win option for China to achieve the "Beautiful China", "Healthy China" and carbon-neutrality goals.