Researchers have developed a sensor system that continuously monitors the air around a person prone to asthma attacks.

A sensor system that continuously monitors the air around people prone to asthma attacks could help researchers understand the causes.

The Georgia Tech Research Institute-developed sensor system measures airborne exposure to formaldehyde, carbon dioxide, ozone, nitrogen dioxide, temperature, relative humidity and total volatile organic compounds, which are emitted as gases from products such as paints, cleaning supplies, pesticide formulations, building materials and furnishings, office equipment and craft materials.

In addition, 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 also can 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 Technologies.

"The device weighs less than one pound including batteries and it takes a measurement of air every two minutes, stores the data in onboard memory and then sleeps to conserve battery power," Jones said.

GTRI principal research scientist Charlene Bayer and colleague 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.

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. 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 of automobile exhaust and gasoline fumes from the garage into the house.