National Atmospheric Deposition Program 2016 Annual summary: 21 Years of MDN

Highlights: NADP data were used in: 248 journal articles; six dissertations; five master’s theses; and twelve agency reports. The Mercury Litterfall Initiative with U.S. Geological Survey (USGS) scientists completed its fifth year of operation. Twenty-six sites collected litterfall (e.g., leaves, twigs, etc.) to measure mercury.• NADP continued its collaboration with USGS scientists to measure atmospheric isotopes of mercury at ~20 NADP sites. • The Total Deposition Science Subcommittee (TDEP) continued its work with U.S. Environmental Protection Agency (USEPA) scientists to estimate dry deposition of nitrogen, sulfur, and other analytes. • TDEP published a Map Summary for 2015. • TDEP continued to collaborate with Environment Canada to estimate mercury dry depo-sition using AMNet data. • TDEP was renewed as a Science Subcommittee for an additional four years.• NADP collaborated with Utah State University to monitor dry deposition as part of a pilot study.• The OTT Pluvio2-L raingage was accepted for network use.• The Aeroallergen Monitoring Science Committee was established.• NADP continued to work with the Council of State and Territorial Epidemiologists (CSTE) on a possible monitoring network for airborne allergen tracking. Airborne allergens are impor-tant as they contribute to allergic rhinitis (i.e., hay fever) and asthma