Modeling of first plume encounters with precipitation

A regional air pollutant transport model was used to simulate the fate of S emissions in the northeast United States. Hourly calculations were analyzed to describe trajectory characteristics and mass balances as pollutant trajectories first encounter precipitation during transport away from emission sources. Model results include air concentrations of SO₂ and sulfate, dry deposition values, and sulfate concentrations scavenged by precipitation, along with trajectory statistics. Results of sensitivity tests are compared to base case simulations which consider all precipitation events as a means of suggesting priorities for future regional transport model development.