The Atmospheric Integrated Research Monitoring Network (AIRMoN) is a research-based subnetwork of the National Atmospheric Deposition Program (NADP) that is designed to quantify the extent to which changes in emissions affect air quality and atmospheric deposition at selected locations. The overall goals of AIRMoN are to provide regular, timely reports on the atmospheric consequences of emission reductions, as imposed under the Clean Air Act Amendments; to extend these observations to deposition rates that affect sensitive ecosystems; and to provide a direct linkage between the monitoring and modeling communities that are involved. To accomplish these goals, AIRMoN was divided into two components: AIRMoN-dry and AIRMoN-wet. Dry deposition estimates of environmentally significant species, such as ozone (O3), sulfur dioxide (SO2), and nitric acid (HNO3), were routinely generated and, at the program’s inception, provided comprehensive flux information. The archive AIRMoN-dry data remain a highly-referenced, seminal record of field-based dry deposition estimates. The U.S. EPA CASTNET program continues to provide estimates of dry deposition using filterpack data. AIRMoN-wet precipitation sampling has continued without interruption since the adoption of the program by NOAA. Rigorous sampling procedures, developed in conjunction with NADP, ensure that AIRMoN precipitation chemistry and wet deposition estimates are timely and accurate.
Currently, AIRMoN consists of several collocated operational research establishments throughout the eastern U.S. The daily precipitation sampling protocol facilitates quantification of deposition estimates for several species, including ammonium, which is an important consideration to the role of atmospheric deposition in coastal eutrophication. Daily sampling also permits a direct coupling of wet deposition with meteorological factors, contributing to the assessment of fate and transport for all measured quantities. The site operated near ATDD is located in the Walker Branch Watershed, a long-term environmental research area. The watershed is a forest ecosystem typical of Southern Blue Ridge Mountains. Wet deposition studies are especially important in these ecosystems because nutrient imbalances affect plant growth and productivity. AIRMoN data from Walker Branch Watershed is available on the NADP website.