Organic acids in different size classes of atmospheric particulate material

A three-dimensional, Eulerian modeling system was used to study transport of chemical species from North America and Europe to the Atlantic Ocean. A mesoscale meteorological model simulated April 1982 with 10 consecutive 3-day runs. This simulated meteorology drove a chemical model with 24 predicted and transported species, and 11 non-transported (photochemical equilibrium) species. We used artificially clean initial and boundary conditions to investigate the effect of anthropogenic emissions on ozone. Two weeks were needed to “spin up” the chemical model. At individual times, plumes were intermittently found moving out over the ocean from the continental source region. In the planetary boundary layer, the time-average plumes were significantly weakened by vertical transport and aqueous chemistry in clouds. The continental plume of Europe was often more persistent than that from North America. The simulated total fluxes of sulfur (S) and nitrogen (N) from North America to the Atlantic Ocean, in a layer from the surface to 5.5 km high, were in reasonable agreement with data analyses. The eastward, atmospheric flux of S was 4.8 Tg/yr and that of N was 1.8 Tg/yr.