title: Measurements and modeling of reactive nitrogen deposition in southeast Brazil.
abstract: Increased reactive nitrogen (Nr) deposition due to expansion of agro-industry was investigated considering emission sources, atmospheric transport and chemical reactions. Measurements of the main inorganic nitrogen species (NO2, NH3, HNO3, and aerosol nitrate and ammonium) were made over a period of one year at six sites distributed across an area of ∼130,000 km2 in southeast Brazil. Oxidized species were estimated to account for ∼90% of dry deposited Nr, due to the region's large emissions of nitrogen oxides from biomass burning and road transport. NO2-N was important closer to urban areas, however overall HNO3-N represented the largest component of dry deposited Nr. A simple mathematical modeling procedure was developed to enable estimates of total Nr dry deposition to be made from knowledge of NO2 concentrations. The technique, whose accuracy here ranged from <1% to 29%, provides a useful new tool for the mapping of reactive nitrogen deposition.
authors.affiliation: Department of Analytical Chemistry, Institute of Chemistry, State University of São Paulo, CP 355, 14800-900 Araraquara, SP, Brazil. andrew@pq.cnpq.br
authors.forename: A G
authors.initials: AG
authors.lastname: Allen
authors.forename: C M D
authors.initials: CM
authors.lastname: Machado
authors.forename: A A
authors.initials: AA
authors.lastname: Cardoso
mesh_terms: D000336:Aerosols; D000383:Agriculture; D000393:Air Pollutants / Q000032:analysis*; D001938:Brazil; D007221:Industry; D008956:Models, Chemical; D026361:Reactive Nitrogen Species / Q000032:analysis*; D012621:Seasons
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D026361:Reactive Nitrogen Species