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Time-location analysis for exposure assessment studies of children using a novel global positioning system instrument.

Elgethun K; Fenske RA; Yost MG; Palcisko GJ
Environ Health Perspect 2003 Jan; 111(1):115-122
Global positioning system (GPS) technology is used widely for business and leisure activities and offers promise for human time-location studies to evaluate potential exposure to environmental contaminants. In this article we describe the development of a novel GPS instrument suitable for tracking the movements of young children. Eleven children in the Seattle area (2-8 years old) wore custom-designed data-logging GPS units integrated into clothing. Location data were transferred into geographic information systems software for map overlay, visualization, and tabular analysis. Data were grouped into five location categories (in vehicle, inside house, inside school, inside business, and outside) to determine time spent and percentage reception in each location. Additional experiments focused on spatial resolution, reception efficiency in typical environments, and sources of signal interference. Significant signal interference occurred only inside concrete/steel-frame buildings and inside a power substation. The GPS instruments provided adequate spatial resolution (typically about 2-3 m outdoors and 4-5 m indoors) to locate subjects within distinct microenvironments and distinguish a variety of human activities. Reception experiments showed that location could be tracked outside, proximal to buildings, and inside some buildings. Specific location information could identify movement in a single room inside a home, on a playground, or along a fence line. The instrument, worn in a vest or in bib overalls, was accepted by children and parents. Durability of the wiring was improved early in the study to correct breakage problems. The use of GPS technology offers a new level of accuracy for direct quantification of time-location activity patterns in exposure assessment studies.
Children; Environmental-contamination; Environmental-exposure; Environmental-hazards; Environmental-health; Environmental-health-monitoring; Prophylaxis; Protective-clothing; Protective-equipment; Organo-phosphorus-compounds; Organo-phosphorus-pesticides; Pesticide-residues; Pesticides; Pesticides-and-agricultural-chemicals
K. Elgethun, Department of Environmental Health, Box 357234, University of Washington, Seattle, WA 98195 USA
Publication Date
Document Type
Journal Article
Email Address
Funding Amount
Funding Type
Cooperative Agreement
Fiscal Year
Identifying No.
Issue of Publication
Priority Area
Neurotoxic Disorders; Neurotoxic-effects
Source Name
Environmental Health Perspectives
Performing Organization
University of Washington, Seattle, Washington
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division