EPA Science Inventory

GPS-based Microenvironment Tracker (MicroTrac) Model to Estimate Time-Location of Individuals for Air Pollution Exposure Assessments: Model Evaluation in Central North Carolina

Citation:

Breen, M., T. Long, Brad Schultz, J. Crooks, M. Breen, J. Langstaff, K. Isaacs, C. Tan, R. Williams, Y. Cao, A. Geller, R. Devlin, S. Batterman, AND T. Buckley. GPS-based Microenvironment Tracker (MicroTrac) Model to Estimate Time-Location of Individuals for Air Pollution Exposure Assessments: Model Evaluation in Central North Carolina. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 24(4):412-420, (2014).

Description:

A critical aspect of air pollution exposure assessment is the estimation of the time spent by individuals in various microenvironments (ME). Accounting for the time spent in different ME with different pollutant concentrations can reduce exposure misclassifications, while failure to do so can add uncertainty and bias to risk estimates. In this study, a classification model, called MicroTrac, was developed to estimate time of day and duration spent in eight ME (indoors and outdoors at home, work, school; inside vehicles; other locations) from global positioning system (GPS) data and geocoded building boundaries. Based on a panel study, MicroTrac estimates were compared to 24 h diary data from 7 participants on workdays and 2 participants on nonworkdays, with corresponding GPS data and building boundaries of home, school, and work. MicroTrac correctly classified the ME for 99.5% of the daily time spent by the participants. The capability of MicroTrac could help to reduce the time-location uncertainty in air pollution exposure models and exposure metrics for individuals in health studies.

Purpose/Objective:

The National Exposure Research Laboratory’s (NERL’s) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA’s mission to protect human health and the environment. HEASD’s research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA’s strategic plan. More specifically, our division conducts research to characterize the movement of pollutants from the source to contact with humans. Our multidisciplinary research program produces Methods, Measurements, and Models to identify relationships between and characterize processes that link source emissions, environmental concentrations, human exposures, and target-tissue dose. The impact of these tools is improved regulatory programs and policies for EPA.

URLs/Downloads:

Journal of Exposure Science & Environmental Epidemiology   Exit

ORD-005050 - BREEN FINAL FINAL.PDF   (PDF,NA pp, 710.373 KB,  about PDF)

Record Details:

Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Start Date: 07/09/2014
Completion Date: 07/09/2014
Record Last Revised: 07/09/2014
Record Created: 07/09/2014
Record Released: 07/09/2014
OMB Category: Other
Record ID: 280636

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL EXPOSURE RESEARCH LAB

HUMAN EXPOSURE AND ATMOSPHERIC SCIENCES DIVISION

EXPOSURE MODELING RESEARCH BRANCH