<p>Wind farms have been found to alter local and regional meteorology and climate. Here, we show that multiple large-scale wind farms might disturb air quality forecasts and affect PM<sub>2.5</sub> air pollution. We explore the impact of large-scale wind farms on PM<sub>2.5</sub> concentrations and forecasts in the Northern China Plain in winter and summer using a coupled weather forecast – atmospheric chemistry model (WRF-Chem). Modelling results reveal that the large-scale wind farms decrease PM<sub>2.5</sub> levels within the wind farms and increase PM<sub>2.5</sub> concentrations by 49 % and 16 % of the modelled monthly mean PM<sub>2.5</sub> concentrations in proximate areas and regions hundreds of kilometres downstream. The wind farm-forced changes in PM<sub>2.5</sub> are more evident in the simulated hourly PM<sub>2.5</sub> concentrations. The model sensitivity studies reveal that hourly concentration fractions in winter induced by wind farms vary from −40 % to 250 % in nearby and distant downstream regions and metropolises, comparing with the cases without the wind farms. The impact of wind farms on modeled PM<sub>2.5</sub> during the nighttime is stronger than that in the daytime. Our results suggested that the wind farm perturbed changes in PM<sub>2.5</sub> should not be overlooked because such changes might affect air quality forecast on an hourly basis, particularly in heavily contaminated Beijing–Tianjin–Hebei region by PM<sub>2.5</sub>.</p>