Effectiveness of emission control in reducing PM<sub>2.5</sub> pollution in central China during winter haze episodes under various potential synoptic controls

Abstract. Currently, mitigating severe particle pollution in autumn and winter is the key to further improving air quality of China. The source contributions transboundary transport fine particles (PM2.5) episodes are closely related large-scale or synoptic-scale atmospheric circulation. How effectively reduce emissions control haze under different synoptic conditions rarely reported. In this study, we classify over central China from 2013 2018 by using Lamb–Jenkinson method National Centers for Environmental Prediction/National Center Atmospheric Research (NCEP/NCAR) Final (FNL) operational global analysis data. effectiveness emission PM2.5 during potential controls simulated GEOS-Chem model. Among 10 identified patterns, four types account 87 % total days. Two typical modes characterized low surface wind speed stable weather high relative humidity (A C type) due a high-pressure system southwest trough low-pressure system, blocking pollutants dispersion. Sensitivity simulations show that these two heavy processes mainly contributed local sources with ?82 A type ?85 type, respectively. other patterns lead characteristics affected northerly southerly winds (NW SW type), carrying northern southern contribution transmission 36.9 7.6 %, respectively PM2.5, contribute 41 69 We also estimate reduction processes. By only reducing SO2 NOx not controlling NH3, enhanced nitrate counteracts effect sulfate on mitigation, less than 4 decrease PM2.5. addition, mitigate NW- SW-type synoptic-controlled episodes, actions should be coordination regional collaborative actions.