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HUMAN EXPOSURE ACTIVITY PATTERNS
The two main objectives of this research are (1) to improve and update and (2) to analyze the CHAD database.
For objective 1, we will
* Reconfigure the CHAD program into a completely modularized Oracle database.
* Redesign User Interface for effcient utilization of the program's capability.
* Obtain dates for those surveys that did not provide them to us, so that we can obtain associated meteorological/climatic inputs for the person-days of information without them.
* Revise the upper and lower bound delimiters in the energy expenditure distributions used for activity-specific estimates.
For objective 2, we will
* Evaluate data quality.
* Evaluate trends and activities for various subgroups.
* Identify temporal patterns for longitudinal data.
* Characterize resolution required for output for exposure and dose models.
Human activity/uptake rate data are necessary to estimate potential human exposure and intake dose to environmental pollutants and to refine human exposure models. Personal exposure monitoring studies have demonstrated the critical role that activities play in explaining and predicting variation in exposure and intake dose from all media. NERL has undertaken a number of activity surveys, including the NHAPS (National Human Activity Pattern Survey), and combined its data and others into CHAD (Consolidated Human Activity Database). CHAD is a relational data base with a graphical user interface that was on EPA's internet system (GOTOBUTTON BM_1_ http://www.epa.gov/chadnet1/), and it facilitates queries by the public and exposure modelers needing activity information. Since inhalation, water consumption, and food ingestion can be related to a personal energy expenditure indicator in CHAD, this database facilitates multi-route exposure/uptake dose modeling. These systems are appropriate for children, adolescents, and adults.
This task description applies to modification and new development work for the CHAD database that will occur in FYs 2005-2007. The work is designed to fill in current gaps in the data and improve the program's functionality.
These improvements are needed so that CHAD becomes more robust than it currently is. The type of information stored in CHAD is necessary because human exposure/dose models require that activity level data be available to estimate the time that exposed people spend in various microenvironments and the activity levels (inhalation, ingestion, and dermal absorption rates) associated with the activities of individuals are of concern from a health effects viewpoint. In addition, the research conducted under this Task will address important issues related to undertaking longitudinal multi-media exposure and dose modeling efforts through analysis of data.