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THE NATIONAL EXPOSURE RESEARCH LABORATORY'S COMPREHENSIVE HUMAN ACTIVITY DATABASE
Citation:
McCurdy, T R., W C. Nelson, Y. Lakkadi, G. Glenn, L. Smith, M. del ValleTorres, AND J. A. Trippett. THE NATIONAL EXPOSURE RESEARCH LABORATORY'S COMPREHENSIVE HUMAN ACTIVITY DATABASE. Presented at International Society of Exposure Analysis, Athens, Greece, September 5-8, 1999.
Description:
EPA's National Exposure Research Laboratory (NERL) has combined data from nine U.S. studies related to human activities into one comprehensive data system that can be accessed via the world-wide web. The data system is called CHAD-Consolidated Human Activity Database-and it is available at http:/epa.gov/
CHAD contains almost 17,000 person-days of activity. All ages and both genders are included in the database, and information regarding every activity undertaken during a day is included in sequential order. For each person in CHAD, the day goes from midnight-to-midnight. Three types of data are available for each Risk Assessment activity: a "macro" location code, an activity code, and an estimate of the metabolic (energy) cost of the activity. Thus, the data are suitable for modeling the time sequence of acute exposures and intake doses, or the data can be aggregated for longer time periods within a day.
CHAD uses about 140 activity codes and 110 location codes, but data are not available for all of these items for all studies; therefore, both sets of codes are organized in a hierarchal manner so that detailed data can has been used if available. Otherwise an aggregated category (e.g., "residence indoor" rather than "kitchen") must be used. Energy expenditure
estimates available for each activity are in terms of METS: metabolic equivalents of work normalized to a person's basal metabolic rate. The METS estimates also account for the phenomenon of EPOC: excess post-exercise oxygen consumption, so that better accounting for energy expenditure after a large exercise event can be accomplished. The paper includes an example of how CHAD can be used to provide estimates of inhalation and ingestion intake rates for children.
This work has been funded wholly or in part by the United States Environmental Protection Agency under contract 68-D5-0049 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved for publication.