Modulation of wintertime PM2.5 concentration in the Fenwei Plain by Eurasian-like pattern and its future projection

The Fenwei Plain (FWP) has experienced the most serious winter PM_2.5 pollution in China since 2000. This study investigates causes behind interannual variability of wintertime PM_2.5 concentration in the FWP during 2000–2021 and projects future trends through integrated observations, reanalysis data and simulations. The results show that the Eurasian-like (EUL) pattern is responsible for the interannual variability of PM_2.5 concentration in the FWP, accounting for up to 55 % of the dominant pollution mode in the region. The EUL pattern modulates PM_2.5 anomalies by causing higher relative humidity, more stable atmospheric stratification and anomalous southeasterly wind. Additionally, based on an EUL index, this study further projects that large-scale atmospheric circulation may exacerbate PM_2.5 pollution in the FWP during 2035–2060. Specifically, the EUL pattern exhibits greater extremity and a higher frequency under high emission scenarios (i.e., 39.9 % in SSP585) compared to low emission scenarios (i.e., 19.9 % in SSP245), suggesting increased frequency of the EUL pattern and the associated PM_2.5 pollution events in the FWP after 2035 in high emission scenarios. These insights provide scientific support for prevention and control of PM_2.5 pollution in the FWP in winter.