The U.S. Geological Survey National Atmospheric Deposition Program, National Trends Network, 2023

The U.S. Geological Survey (USGS) has been a National Atmospheric Deposition Program (NADP) partner agency since 1981. NADP is composed of five atmospheric monitoring networks that verify Clean Air Act effectiveness and provide essential data to protect human health and preserve ecosystems for current and future generations. Stakeholders include land management agencies overseeing sensitive habitats (the National Park Service, Bureau of Land Management, U.S. Forest Service, and Tribes), Federal and State regulatory agencies, and the public.

NTN N-CON Systems Company, Inc., systems collector.*

Valid NTN samples collected in 2023

For more information about the U.S. Geological Survey National Atmospheric Deposition Program: Visit https://www.usgs.gov/mission-areas/water-resources/science/national-atmospheric-deposition-program-nadp Contact the National Atmospheric Deposition Program Coordinator at waternetworks@usgs.gov [This product updates data within the same text from General Information Product 244] NTN site at KY35 Clark State Fish Hatchery, Rowan County, Kentucky (USGS station 380706083324900). This and all other images and figures in this product are from the USGS NADP.

The USGS participates in three NADP monitoring networks: the National Trends Network (NTN), the Mercury Deposition Network, and the Mercury Litterfall Network. The USGS provides resources in addition to scientific and technical support for 80 of the 263 NTN sites, making it one of the largest scientific contributors among the network partner agencies. Weekly precipitation samples are collected at NTN sites, then shipped and analyzed for chemical constituents at a central laboratory. The data are then used for producing atmospheric deposition maps which are used to assess the effectiveness of the Clean Air Act.

NTN sites funded by the USGS Atmospheric chemical constituents analyzed NADP sites and United States 2023 ammonium deposition in kilograms per hectare (kg/ha). Data accessed July 3, 2025, at https://nadp.slh.wisc.edu.

Site OH71 yearly sulfate (SO42-) deposition in kilograms per hectare (kg/ha), recorded at Wooster Exp Sta Weather Station at Wooster OH (USGS station 404700081550000). Image accessed July 1, 2025, at https://nadp.slh.wisc.edu/sites/ntn-OH71/.

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