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National Atmospheric Deposition Program (NADP)

Since 1981, the USGS has been the lead Federal agency for the monitoring of wet atmospheric deposition (chemical constituents deposited from the atmosphere via rain, sleet, and snow) in the United States for the interagency National Atmospheric Deposition Program (NADP).

The USGS supports about one-third (72 of approximately 250) of the NADP-National Trends Network sites, which measure acidity, sulfate, nutrients and other major ions in precipitation. The USGS also supports sites in the 100-site NADP-Mercury Deposition Network and the NADP-Mercury Litterfall Network. These networks provide scientists, resource managers, and policymakers with long-term, high-quality atmospheric deposition data used to support research and decision-making in the areas of air quality, water quality, agricultural effects, forest productivity, materials effects, ecosystem studies, watershed studies, and human health.


Stakeholder Quotes 

Litterfall and throughfall monitoring for mercury dry deposition
Litterfall and throughfall monitoring for mercury dry deposition.

NADP has played a key role in providing long-term monitoring data to assess policies aimed at reducing air pollution and ecological impacts of atmospheric deposition. The program includes monitoring networks for programs including acid rain, mercury, and reactive nitrogen. Policy implementation for acid rain mitigation is relatively mature and the evolution of these policies is reflective in NADP monitoring data. Programs for regulating mercury and reactive nitrogen deposition are less mature and NADP monitoring will be critical in future years to assess control program efficacy.”  

James Schauer, PhD, PE, MBA, Director, Wisconsin State Laboratory of Hygiene, August 2018