National Atmospheric Deposition Program Monitoring precipitation chemistry since 1978 About Contacts Networks National Trends Network NTN SOPs PFAS Sub-Network (PFN) NTN Gradient Maps NTN Interactive Site Map Mercury Deposition Network MDN SOPs MDN Gradient Maps MDN Interactive Site Map Passive Hg Pilot Network Ammonia Monitoring Network AMoN SOPs ALPHA Passive Ammonia Study AMoN Interactive Map AMoN Annual Maps Atmospheric Mercury Network AMNet Interactive Map AMNet Annual Boxplots Passive Hg Pilot Network Mercury Litterfall Network NADP Precipitation Network Sample Archive Request Archived Networks Interactive Map - All NADP Sites Publications Annual Data Summaries NADP Governance Handbook Brochures Bibliography Lists NADP in the news Program Reports Conferences Meetings Scientific Symposiums Spring Meeting & Scientific Symposium Committees About NADP Committees Joint Committees Network Operation Subcommittee (NOS) Education and Outreach Subcommittee (EOS) Critical Loads of Atmospheric Deposition Science Committee (CLAD) Total Deposition Science Committee (TDep) Aeroallergen Monitoring Science Committee (AMSC) Mercury in the Environment and Links to Deposition Science Committee (MELD) Executive Committee Operator Support View Precipitation Data Upload Precipitation Data Network SOPs Quality Assurance Joining NADP News Education NTN Slide National Trends Network The NTN provides a long-term record of the acids, nutrients, and base cations in the U.S. Precipitation MORE MDN Slide Mercury Deposition Network The MDN provides data on the geographic distributions and trends of mercury in precipitation. MORE AMoN Slide Ammonia Monitoring Network The AMON measures air concentration of ammonia using passive monitors MORE AMNet Slide Atmospheric Mercury Network The AMNet reports atmospheric mercury concentrations for determination of mercury dry deposition. MORE MLN Slide Mercury Litterfall Network The MLN provides an estimate of an important component of mercury dry deposition to a forested landscape MORE Highlights 2026 Scientific Symposium Recordings Available TDep Webinar #2: Dr. Amy Christiansen EOS Newsletter: Spring 2026 USGS: Exploring Atmospheric Deposition Chemistry Data Across the United States Next NADP Coordinator Announced NTN Data Export corrections NADP Fact Sheet available Upcoming Events Meetings NACAA National Air Quality Conference August 10-13, 2026 Omaha, NE NADP Fall Business Meeting October 27-29, 2026 Webinars TDep Webinar #3: Dr. Kang Sun August 27, 2026 COMMITTEES NOS EOS CLAD TDep AMSC MELD Home Contacts Operator Support Data Use Conditions Comments? FOLLOW US © 2026 Board of Regents of the University of Wisconsin System