Contemporary rates of atmospheric inorganic nitrogen (N) deposition to Latin American cities

Recent efforts to develop and evaluate regional and global chemical transport models reveal major gaps in atmospheric deposition monitoring. First, in contrast to northern North America, western Europe, and Asia, vast land areas in Latin America, Africa, and Australia remain under-sampled. Organized networks that monitor atmospheric deposition in these regions are few in number or nonexistent. Second, urban areas, important deposition ‘hotspots’, less well represented in atmospheric deposition monitoring networks. Third, many monitoring networks estimate only wet deposition, even though dry deposition can comprise a significant fraction of the total material deposited to ecosystems, especially in arid environments and in cities. This study used the GEOS-Chem model to simulate deposition in South America. Model values are compared with available observed wet deposition data and the spatial patterns of observed and modeled deposition were generally consistent. The model was able to provide additional spatial coverage of deposition as well as estimates of dry deposition.