Effect of meteorological variability on fine particulate matter simulations over the contiguous United States

Weather Research and Forecasting-Advanced Research WRF (WRF-ARW) simulations reproduced the variability of surface temperature very well but overestimated the 10-m wind speed, precipitation, and at some sites the planetary boundary layer height. Averaged over CONUS, CMAQ simulations driven by all three meteorological configurations capture the observed daytime low and nighttime high PM2.5 mass concentrations but underestimated the observed concentrations likely due to faster advection and higher wet deposition in the model.

PM2.5 levels across the three simulations agreed well during daytime but showed larger variability during nighttime due to dominance of aerosol, clouds, and advection processes in nighttime. The meteorology-induced variability in PM2.5 is estimated to be 0.08-24 g/m(3) over the CONUS with larger variability over the eastern United States.