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NNOVATIVE RESEARCH FOR A SUSTAINABLE FUTURE

Microenvironment Tracker (MicroTrac): Personal Time-Activity Modeling

GPS data loggers like this one collect information on a person's location and
speed for input into MicroTrac.

Background

To better understand people's
contact with pollutants and their
potential for adverse effects, it's
important to estimate how much
time people spend in different
locations and what activities they
do there. Using questionnaires to
collect this information has
limitations, including the burden on
participants and inaccuracies in
questionnaire responses.

To address these limitations, there
is a growing commitment to use
common personal electronic
devices - like smart phones, global
positioning systems (GPS), and
movement sensors - to collect
exposure data on personal
activities that can be integrated
with personal pollutant and health
monitoring devices.

What is MicroTrac?

MicroTrac is a model developed by
EPA that uses GPS data to
estimate time of day and duration
that people spend in different
microenvironmenfs, such as
indoors and outdoors at home,
work, school, and inside vehicles.

Using MicroTrac can improve
exposure assessments for health
studies by helping air pollution
scientists determine location and
physical activity of study
participants prior to adverse health
effects. Using smart phones with
these data collection capabilities
will facilitate and expand the use of
MicroTrac in health studies, and

will support community applications
of MicroTrac, such as modifying
behavior for susceptible individuals
like asthmatics.

How is MicroTrac being used?

MicroTrac has been evaluated
using a pilot study in central North
Carolina, and additional
evaluations are ongoing with North
Carolina State University and Hong
Kong University of Science and
Technology. The model is being
applied for various health studies,
including a childhood asthmatic
health study in Detroit, and a
cardiovascular health study in
North Carolina.

This research can improve
exposure assessments for health
studies that provide a scientific
basis for air pollution regulations,
and for creating public health
strategies that help vulnerable
people reduce their exposure to air
pollution.

Next steps for MicroTrac

EPA scientists are currently
developing a smart phone
application called MyAir that will
allow/ MicroTrac users to predict
their exposure to outdoor-
generated air pollution. The app is
being currently being developed for
iPhone only, and will likely become
available for download via the App
Store. Developers have not yet set
a release date for the app.

Learn more about MicroTrac and
download the model at:

www.epa.gov/air-
research/microenvironmenl-
tracker-microtrac-model-helps-
track-air-qualitv

CONTACTS

Technical Contact:

Michael Breen

breen.michael@epa.qov

Media Contact:

Emily Smith

smith.emilv@epa.gov

1

U.S. Environmental Protection Agency

Office of Research and Development

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