The horizontal transport of O3, SO2, and non-sea-salt particulate SO=4 over the ocean near Nova Scotia, Canada, is determined from in situ measurements made during the 1993 North Atlantic Regional Experiment (NARE) summer intensive. The average mass of O3 transported through an area 1 m in horizontal extent and 5 km in the vertical is 2.8 g s-1, moving from west to east. Anthropogenic O3 accounts for 50% of the transport below 1 km, 35--50% from 1 to 3 km, 25--50% from 3 to 4 km, and 10% from 4 to 5 km. The average mass of SO2 and SO=4 transported through the same area is 50 mg S s1, moving from west to east. Eighty percent of the SO=4 and 55% of the SO2 are transported above 1 km, with little transport of these species seen above 3 km. The anthropogenic input of O3 and S to the North Atlantic atmosphere from the North American continent is estimated. ¿ American Geophysical Union 1996