Modeling of pollutant transport and removal during a regional sulfate episode

As part of a multidisciplinary study performed for the National Commission on Air Quality, the phenomena of atmospheric transport and the removal of SO₂ and SO₄ ^? during a major regional sulfate episode (the period July 18–25, 1978 in the eastern U.S.) had been examined. The main objective of this study was the evaluation and the quantification of varying source/receptor relationships under atmospheric conditions conducive to long-range transport of fine particulate matter. In the case study presented here, air mass trajectories were obtained using the numerical NMC trajectory predictions and the results of the isobaric trajectory computations at the 850 mb level. The effects of alternative regional SO₂ emission reduction scenarios on the predicted ambient SO₂ and SO₄ ^? concentrations were also investigated using the new modeling methods that were specifically developed for this purpose.