National Atmospheric Deposition Program 2009 Annual Summary

The National Atmospheric Deposition Program (NADP) provides data that support informed decisions on environmental issues related to precipitation, deposition chemistry, and atmospheric mercury species. NADP data are relevant to scientists, educators, policymakers, and the public. All data are available free of charge via the website (http://nadp.isws.illinois.edu). Products available on this site include seasonal and annual averages, time series trend plots, concentration and deposition maps, and reports. In 2009, the NADP processed 13,214 samples from the 250-site National Trends Network (NTN), 1,297 samples from the 7-site Atmospheric Integrated Research Monitoring Network (AIRMoN), and 6,748 samples from the 115-site Mercury Deposition Network (MDN). The Atmospheric Mercury Network (AMNet) provided nearly 36,400 valid observations. The NADP website is the primary tool for disseminating data from the four NADP networks. There are approximately 40,000 registered users on the site. In 2009, the site was accessed approximately 1.65 million times and had 90,000 unique visitors. Data were downloaded more than 26,000 times during the year. Users of the NADP website include federal and state agencies, universities, and primary and secondary (K-12) schools. Eighty-five percent of the data downloads relate to acid and nutrient species; the remaining 15 percent relate to mercury in wet deposition.published or submitted for publicationis peer reviewe