In the extreme winters of Interior Alaska, air quality in Fairbanks often violates the new EPA regulations for PM2.5. Simulations from past cases performed with the Weather Research and Forecasting (WRF) model online coupled with a chemistry model known as WRFchem will be presented. Focus will be on (1) how well WRF captures these synoptic situations and (2) the processes for the formation of poor air quality. Preliminary results show that WRFchem well captures the temporal evolution of wind-speed, 2m-temperature and acceptably predicts dew point temperature and relative humidity. Model results will be compared to PM2.5 observations.