Assessment of the emission mitigation effect on the wintertime air quality in the Guanzhong Basin, China from 2013 to 2017

Abstract

With the completion of the Air Pollution Prevention and Control Action Plan (Action Plan) in the Guanzhong Basin (GZB), the wintertime fine particulate matters (PM2.5) concentration has decreased by 50.0 μg m−3 (33.4%) from 2013 to 2017. Considering the significant impacts of meteorological conditions on particulate pollution, the effectiveness of anthropogenic emissions abatement on the PM2.5 reduction in the GZB remain unclear. In this study, the WRF-Chem model was used to quantitatively evaluate the effectiveness of emissions mitigation on the particulate pollution in the GZB in December from 2013 to 2017. The model typically showed an affordable consistence with observations and simulation in meteorological parameters, atmospheric pollutants, and aerosol components. Sensitivity results revealed that emissions reduction decreases PM2.5 concentrations by around 17% in the GZB, about half of the observed PM2.5 decreased in December from 2013 to 2017, showing significant role of meteorological conditions in modulating particulate pollution. Emissions mitigation also decreased SO2, CO and O3 concentrations by around 55%, 17%, and 7%, respectively, but increased NO2 concentrations by 27%. Additionally, the PM2.5 decrease in the GZB is mainly contributed by the reduction of sulfate and primary organic aerosols, caused by implementation of stringent SO2 mitigation measures and reduced coal use. However, the mitigation of elemental carbon, dust and nitrate aerosols are not significant, particularly with regarding to nitrate aerosols, which is influenced by increase of NO2 and decrease of sulfate. Specified emissions mitigation strategies need to be designed to further lower the PM2.5 level in the GZB.