Urban wet deposition nitrate: A comparison to non-urban deposition

The concentration of nitrate in both wet and dry deposition has both increased historically and currently, and recently parallels emissions in NO_x. Since NO_x is produced in amounts comparable to SO₂, it is an important contributor to acid deposition, and is produced in higher amounts in urban areas due to concentrated sources. Prior to this study, national acid deposition monitoring networks in the United States have been and remain established in non-urban areas. This research study consisted of a comparison of precipitation sampling and analysis of wet deposition nitrate and pH for each deposition event in each of two urban sites over a 15 mo period. Also, a comparison of urban data and data generated at a nearby non-urban NADP site was made by examination of both monthly and seasonal data. This research suggests that national monitoring programs should consider inclusion of urban and non-urban monitoring sites in order to achieve a more representative regional assessment.