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Consolidated Human Activity Database (CHAD)

The CHAD database includes nearly 180,000 individual study days of detailed human behavior, with each day broken down into individual hours and activity types. The data include demographic information such as age, sex, employment, and education level, which allows researchers to examine specific groups within the general population and how their unique behavior patterns influence their exposures to chemicals.

The data in CHAD can help researchers understand the patterns of human behavior that influence their exposure to chemicals in their environment. In addition, data from CHAD are routinely used by EPA and other government agencies, academia, and private organizations for human exposure and health studies, and in models used for exposure and risk assessment.

2019-2020 Version of CHAD

Previous versions of CHAD

Technical Contacts:

John Langstaff (

Stephen Graham (