Science Inventory



OZKAYNAK, H. A. EXPOSURES TO ENVIRONMENTAL AGENTS. Presented at Time-Use Data for the National Children's Study Workshop, Arlington, VA, December 09 - 10, 2004.


The primary objective of this research is to produce a documented version of the aggregate SHEDS-Pesticides model for conducting reliable probabilistic population assessments of human exposure and dose to environmental pollutants. SHEDS is being developed to help answer the following questions:

(1) What is the population distribution of exposure for a given cohort for existing scenarios or for proposed exposure reduction scenarios?

(2) What is the intensity, duration, frequency, and timing of exposures from different routes?

(3) What are the most critical media, routes, pathways, and factors contributing to exposures?

(4) What is the uncertainty associated with predictions of exposure for a population?

(5) How do modeled estimates compare to real-world data?

(6) What additional human exposure measurements are needed to reduce uncertainty in population estimates?


The planned interagency National Children's Study (NCS) will be studying a number of exposure issues in the context of health and well-being of infants and young children from pre-conception to age 21. Some of the important environmental exposure questions for NCS, include: how can we best determine children's exposures to various environmental agents by different life stages?; which locations, sources, media, routes and pathways contribute greatest to exposures of interest?; what activities and behaviors influence the pollutant transfer rates, exposures, uptake and dose?, and; what are the measures of exposures of health relevance (e.g., duration, intensity, timing, frequency). Administering well-designed time-activity data, supplemented with household questionnaires, is an important aspect of the exposure analysis component of the NCS. Time-activity data are intended to provide information on the types and locations of sources of exposures and allows estimation of exposure durations and delivered dose using physiological data and exertion level information. In conjunction with microenvironmental concentration measurements, time-activity data enables estimation of exposure concentrations and time-sequence of personal exposures. Types of time-use data collection instruments include: self-reported diaries; video and camera techniques; voice recording devices; combined technologies (e.g. GPS for time and location, motion sensors for activity level, miniature cameras for location and microactivity), and; questionnaires for gathering specific information on subjects and households, consumer product use, building factors, etc. This presentation will give examples of typical time-activity diary formats used in exposure field studies and how they are used in calculating route-specific exposure estimates and total dose for children exposed to pollutants indoors and outdoors.

This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.

Record Details:

Product Published Date: 12/09/2004
Record Last Revised: 06/21/2006
Record ID: 131429