Comparison of the Performance of AERMOD and CALPUFF Dispersion Model Outputs to Monitored Data

Abstract

AERMOD and CALPUFF are two Ontario approved regulatory air dispersion models used to assess air quality compliance to provincial standards. Modelled results from these dispersion models may not always be representative of actual concentrations due to their inherent assumptions and atmospheric simplifications. This research aims to assess the near field performance of these two models by comparing modelled concentrations predictions with monitored observations. The case study analyzed was for 24 h average nickel (Ni) from a Facility located in Northern Ontario. The Facility has a monitoring program set up to measure dust, from which the monitored metal concentrations were speciated. Statistical analysis of the modelled results demonstrated that CALPUFF 24 h average modelled concentrations showed better agreement with monitored results than those modelled using AERMOD, however, even these CALPUFF results were often 2x (or 0.5x) the monitored value.