The CHAD Database

The Consolidated Human Activity Database (CHAD) contains detailed data about the activities performed by a sample of the U.S. population together with geographic and demographic information. The data were collected in 12 studies performed in the cities of Baltimore, Cincinnati, Denver, Los Angeles, Valdez (Alaska), and Washington, DC, in the state of California and nationwide by the University of Michigan and by NHAPS (National Human Activity Pattern Study). Due to the fact that the majority of the study was carried out on a local basis, certain groups of the American population are oversampled.
The database contains 2 tables:

  • Subject table
  • Activity table

The Subject Table contains demographic information, including age, gender, race, 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 Activity Table contains records with the activity diary of each subject in the database. Each activity day is broken down into individual hours and activity type. Together with the start and ending times of the recorded activity, the location where the activity has been performed is recorded. Further, the Activity Table provides data about whether the subject had heavy breathing and a high/low metabolic rate while performing the activity. A descriptive statistical analysis of these locations is reported in George, B., & McCurdy, T. (2011)

George, B., & McCurdy, T. (2011). Investigating the American Time Use Survey from an exposure modeling perspective. Journal of Exposure Science and Environmental Epidemiology, 21,92-105.