The synergistic effects of various air pollutants on meteorological fields have not yet been widely studied and fully understood, especially at the junction of the Loess Plateau, Mongolian Plateau and Tibetan Plateau. Two experiments were carried out with and without the incorporation of air pollutants to explore the synergistic effects using the Weather Research and Forecasting (WRF) model and WRF model coupled with chemistry (WRF-Chem) at the junction of the above three plateaus. The incorporation of air pollutants led to negative and positive variation patterns of meteorological fields and improved the simulation accuracy of meteorological factors to some extent. The negative variation pattern was caused by the direct absorption and scattering of solar radiation by air pollutants, and the positive variation pattern was driven by the evaporation of clouds due to the synergistic semidirect effects of air pollutants, which was more significant in this region. In the positive variation pattern, the solar radiation flux reaching the ground and the outgoing longwave radiation at the top of the atmosphere were increased by approximately 2–8% and 1–4%, respectively, the surface was warmed by 0.2–0.6 K, planetary boundary layer height (PBLH) increased by 3–12%, and relative humidity (RH) decreased by 1–4%. Moreover, the change in wind speed was approximately −0.3–0.3 m/s in the region. Furthermore, the correlation of conventional air pollutants with changes in meteorological factors indicated that there were not simple linear effects of atmospheric pollutants on meteorological fields and that considering a single pollutant cannot reflect the synergistic effects of various air pollutants on meteorological fields. This study quantifies the synergistic effects of various air pollutants on meteorological fields, which is a key issue that cannot be ignored in the modelling of meteorological fields and in the exploration of the interactions between air pollutants and synoptic weather.