Assessing Atmospheric Deposition of Mercury in Florida, USA: Local versus Global Sources and Models versus Measurements

We compare results from the CMAQ photochemical model for mercury deposition in Florida with measurements from 2009 associated with the Florida Mercury TMDL project, with focus on the question: can model predictions for the impact of local versus global emissions be validated versus measurements? Model wet deposition shows reasonable agreement with measurements, and the lack of variation between sites in Florida in both model and measurements is consistent with the model prediction for limited impact from local sources. Local sources have a larger impact on dry deposition. However, the model overestimates ambient RGM by a factor of 10 versus measured values.