An official website of the United States government.

We've made some changes to If the information you are looking for is not here, you may be able to find it on the EPA Web Archive or the January 19, 2017 Web Snapshot.

Clean Air Markets

Publications Drawing on TIME/LTM Data, 1985-2007

EPA oversees the Long Term Monitoring (LTM) and Temporally Integrated Monitoring of Ecosystems (TIME) programs to track the status of acidified and acid-sensitive waters. These programs measure critical chemical variables which provide insights into many measures of ecosystem health. The LTM and TIME programs are complementary monitoring networks used to better understand long-term trends in acidification and recovery in the Northeastern and Mid-Atlantic United States. Both programs are operated with numerous collaborators in state agencies, academic institutions and other federal agencies.

View Monitoring Surface Water Chemistry for more detailed information about the LTM and TIME monitoring programs.

View a list of publications that have drawn on LTM and/or TIME data below.

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.