The National Acid Precipitation Assessment Program (NAPAP) is a cooperative federal program first authorized in 1980 to coordinate acid rain research and report the findings to Congress. The research, monitoring, and assessment efforts by NAPAP and others in the 1980s culminated in Title IV of the 1990 Clean Air Act Amendments, also known as the Acid Deposition Control Program.

In a bold new approach to environmental protection, Title IV includes a market-based program that provides economic incentives for controlling emissions of sulfur dioxide from electricity generating facilities. Title IX of the CAAA reauthorized NAPAP to conduct acid rain research and monitoring and to periodically assess the costs, benefits, and effectiveness of Title IV. The NAPAP member agencies are the U.S. Environmental Protection Agency, the U.S. Department of Energy, the U.S. Department of Agriculture, the U.S. Department of Interior, the National Aeronautics and Space Administration, and the National Oceanic and Atmospheric Administration. The 1996 NAPAP report (5.8 Mb) was the second assessment of Title IV since implementation in 1990.

In 1997 NAPAP began to operate under the auspices of the Committee on Environment and Natural Resources (CENR) of the National Science and Technology Council. NAPAP’s goal continues to be providing credible technical findings on acid deposition and its effects to inform the public decision-making process. To ensure that this goal is met, NAPAP coordinates its activities through the Air Quality Research Subcommittee of CENR.

The most recent NAPAP report published in 2005 (3.0 Mb) was the third assessment of Title IV since implementation in 1990.