The flux of s and n eastward from north America

Using climatological wind data and average concentrations of SO 2, SO 4, NO x NO 3, HNO 3 and PAN from data bases in the United States and Canada we calculate the net atmospheric transport of S and N eastward from North America in eight latitude and three altitude classes. A broad maximum in transport occurs between 33° and 48°N. Of the S and N emitted to the atmosphere of eastern North America, about 34 and 24–71%, respectively, are advected eastward. Transport at all levels between 0 and 5500 m is important.