To measure the air quality, a small motor in the device sucks in air through an intake hose. Before the air passes over the sensors, it encounters a small filter that removes particulates, such as dust and pollen. The mass of the filter is measured before and after a sampling period to determine the total amount of particles. The air is then evenly distributed over the sensors.

"It takes about 30 seconds for the air to pass through the device and the data to be stored, and then it goes to sleep for another minute. In one hour it takes approximately 50 or 60 samples," says Jones.

The device can be worn for up to 24 hours before the particle filter needs to be replaced and the memory on the device is full. The data can be downloaded from the sensor system onto a computer.

Millard says the device is unique and innovative, but that he would like to see its capabilities expanded to measure tobacco smoke. He would also like to be able to separate out the particle measurements so they can be measured in real time--an upgrade that Bayer says will be introduced once the device is commercialized. Bayer would also like to get more specific readings on the different volatile organic compounds.

"We would like to get to the point where we can pop certain sensors in and out so a patient can target it towards their particular needs," says Bayer. "Asthma is a very complicated disease and there are a number of different airborne exposures that can exacerbate an asthma attack. This technology will allow us to find the source of exacerbation and understand the health impacts," she says.

The researchers at GTRI are currently in talks with an undisclosed company to commercialize the device, says Bayer. The initial target users will be asthma patients but the device will be open for use by others who want to study environmental exposures.