A new sensor system that is worn in the
vest is being promoted as a novel method to assess the environmental causes of
asthma by researchers at the Georgia Tech Research Institute (GTRI).
"We are investigating whether we can go
back after an asthma attack and see what was going on environmentally when the
attack started," said Charlene Bayer, a GTRI principal research scientist.
This research was supported by the U.S.
Department of Housing and Urban Development and initial funding from the GTRI
Independent Research and Development (IRAD) program.
Although no one fully understands why
certain people get asthma, doctors know that once a person has it, his/her
lungs can overreact to environmental stimuli causing chest tightness or
breathlessness, known as an asthma attack.
The new sensor system measures airborne
exposure to formaldehyde, carbon dioxide, ozone, nitrogen dioxide, temperature,
relative humidity and total volatile organic compounds (VOCs). VOCs are emitted
as gases from products such as paints, cleaning supplies, pesticide
formulations, building materials and furnishings, office equipment and craft
In addition to detecting the seven
environmental stimuli mentioned above, a special mesh filter collects
particles. A pump pulls air through the filter so that the quantity of particles
can be measured at the end of the sampling period. The composition of the
collected particulate can also be analyzed in the laboratory.
The battery-powered system fits into the
pocket of a vest and contains commercially available sensors that were integrated
into a single system by Mark Jones, chief executive officer of Keehi
"The device weighs less than one pound
including batteries and it takes a measurement of air every two minutes, stores
the data in on-board memory and then sleeps to conserve battery power," said
Bayer and GTRI Research Scientist Robert
Hendry calibrated and tested the sensors in a large room-sized chamber that
simulates real-world environmental conditions inside buildings. Coupled with
sensitive mass spectrometers, the chamber allows the changing indoor air
chemistry to be studied in detail.
The sensor system is designed to be
comfortably worn in the pockets of a vest throughout the day and kept at the
bedside while sleeping at night. Another vest pocket contains an electronic
peak flow meter to periodically measure pulmonary function. When experiencing
an asthma attack, the vest wearer notes what time it occurred and Bayer can
examine the levels of the chemical compounds at that time.
Six adult volunteers have tested the vest
for comfort and the effectiveness of the sensor system under actual use
conditions. And that has already brought benefits for one volunteer, whose vest
detected higher volatile organic exposures in his home than anywhere else. That
led researchers to discover a pollutant pathway from the volunteer's basement
garage into the living areas that was allowing automobile exhaust and gasoline
fumes to invade the house.
With future funding, Bayer hopes to develop
a smaller and more sensitive sensor system, test the current vest in population
studies of asthmatic children and develop software to process the population
studies data as it is collected.
"With this system we can determine what
children are exposed to at home, at school and outside where they play," said
Bayer. "Chances are there are some overreaching compounds that seem to trigger
asthma attacks in more children."