Energy and emission pathways towards PM_2.5 air quality attainment in the Beijing-Tianjin-Hebei region by 2030

In 2013, the Chinese government announced its first air quality standard for PM_2.5 (particulate matter with a diameter < 2.5 μm) which requires annual mean PM_2.5 concentration to achieve the World Health Organization (WHO) interim target 1 of 35 μg/m³ nationwide including the most polluted region of Beijing-Tianjin-Hebei (BTH). Here, we explore the future mitigation pathways for the BTH region to investigate the possibility of air quality attainment by 2030 in that region, by developing two energy scenarios (i.e., baseline energy scenario and enhanced energy scenario) and two end-of-pipe scenarios (i.e., business as usual scenario and best available technology scenario) and simulating future air quality for different scenarios using the WRF/CMAQ model. Results showed that without stringent energy and industrial structure adjustment, even the most advanced end-of-pipe technologies did not allow the BTH region to attain the 35 μg/m³ target. Under the most stringent scenario that coupled the enhanced structure adjustment measures and the best available end-of-pipe measures, the emissions of SO₂, NO_x, PM_2.5 and NMVOCs (nonmethane volatile organic compounds) were estimated to be reduced by 85%, 74%, 82% and 72%, respectively, in 2030 over the BTH region. As a result, the simulated annual mean PM_2.5 concentrations in Beijing, Tianjin and Hebei could decline to 23, 28 and 28 μg/m³, respectively, all of which achieved the 35 μg/m³ target by 2030. Our study identified a feasible pathway to achieve the 2030 target and highlighted the importance of reshaping the energy and industrial structure of the BTH region for future air pollution mitigation.