Air pollution mitigation in North China through flexible heating policies

Central heating in North China produces severe air pollution, although the need for heating may be reduced by rising temperatures associated with climate change. The regional trend of mean heating length (HL) for North China was −0.32 d per year during 1961–2019. Compared with the 2010–2015 mean values, the start and end dates for central heating in the North China Plain (NCP) during 2050–2055 will delayed by 9 d and advanced by 12 d, respectively, under the Shared Socioeconomic Pathway 5–8.5 (SSP5-85), and by 5 and 8 d under the carbon-neutral (CN) scenario, based on Coupled Model Intercomparison Project phase 6 model simulations. Here we propose a flexible heating policy (FHP), such that HL is determined strictly by temperature, and the associated air pollution benefit of shortening HL are examined by a global 3D chemical transport model GEOS-Chem. The study focused on the year 2019 with the current goal of elimination of severe PM _2.5 pollution, and with the minimum HL estimated to provide up to a 24% reduction in severe PM _2.5 pollution (daily mean PM _2.5 > 150 μ g m ^−3 ) over the NCP during periods of FHP implementation. For future CN policies, the NCP can achieve great air quality improvements by 2050, with more than 60% of days throughout the heating season with daily PM _2.5 concentrations of <10 μ g m ^−3 , and 95% with <35 μ g m ^−3 . Although the SSP5-85 scenario may lead to reduced HLs, pollutant emissions are likely much higher than under CN scenarios, with pollution days of PM _2.5 > 100 μ g m ^−3 still occurring frequently by 2050. Our results highlight that FHPs may effectively reduce severe PM _2.5 pollution, and China’s carbon neutrality goals will play critical roles in mitigating air pollution and prolonged heating welfare during future heating season.