EPA maintains the Consolidated Human Activity Database (CHAD). CHAD contains data obtained from pre-existing human activity studies that were collected at city, state, and national levels. CHAD is intended to be an input file for exposure/intake dose modeling and/or statistical analysis. The documents below describe CHAD and its use.You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.
- CHAD Documentation and User’s Guide (PDF)(194 pp, 4 MB, October 2019, EPA-452/B-19-001)
Technical Memo, CHAD-APEX Updates - June 2019 (PDF)(15 pp, 905 K)
Further updates to CHAD