||Illinois State Water Survey Div., Champaign.; Illinois Univ. at Urbana-Champaign.; Department of Agriculture, Washington, DC.; Department of the Interior, Washington, DC.; Environmental Protection Agency, Washington, DC.
This report presents data summaries from three networks. Contour maps present NTN data. Concentration and deposition maps present MDN data. The donut graphs present AIRMoN concentrations over time. The NTN maps portray spatial variability in the concentration and deposition of selected acids, nutrients, and base cations on regional and national scales. Only sites that meet prescribed data completeness criteria are included. In 2000, 175 sites met these criteria. Annual concentration or deposition values are printed next to each site. The concentrations are volume-weighted averages. The MDN maps show the concentration and deposition of total mercury in precipitation. Only sites meeting prescribed data completeness criteria are included. In 2000, 39 sites met these criteria. Annual concentration or deposition is printed next to each site. The concentrations are volume-weighted averages. The AIRMoN data show the inorganic nitrogen deposition from nitrate and ammonium in warm and cold season samples at AIRMoN sites active through 2000. Warm season samples occur in May- October, approximating the northern U.S. growing season. Cold season samples occur in January-April and November-December, approximating the northern U.S. dormant season. Annual nitrogen deposition from nitrate and ammonium was calculated from the total annual precipitation and precipitation-weighted average nitrate and ammonium concentrations. For the Tampa Bay (FL18) site, warm season deposition was about 86 percent of the total, and just nine warm season samples accounted for about half of the annual nitrogen deposition.