Sensors exist to answer questions. Sometimes those questions are fairly specific:, e.g., "Is the room too cold and the furnace needs to kick in?" or "Is this part acceptable?" and sometimes they're far more vague. A current research project is attempting to answer "If you have asthma, what is setting it off?"
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For those of you unfamiliar with asthma, it's a condition in which environmental stimuli cause the lungs to overact—the airway constricts and the unhappy recipient begins to wheeze and experience tightness in the chest and breathlessness. One of the challenges to identifying causes is that the asthma attack may not happen until after exposure to whatever environmental trigger set it off. And until now, there wasn't a good way to quantify which of the various potential triggers (and in what concentration) were present when an attack occurred.
Researchers at the Georgia Tech Research Institute, supported by the U.S. Dept. of Housing and Urban Development, came up with a very clever way of finding out what might have triggered an attack. Volunteers participating in the test wear a special vest which contains an air quality monitoring system in one pocket and a peak flow meter (to measure pulmonary fitness, i.e., how well the lungs are working) in another. The sensor system continuously monitors the air quality around the wearer, checking for the presence of formaldehyde, carbon dioxide, ozone, nitrogen dioxide, temperature, relative humidity, and volatile organic compounds (VOCs). A mesh filter also collects samples of airborne particulates which can be analyzed later in a lab.
During the day, the person wears the vest and measures his or her pulmonary function periodically. At night, the sensor system is set by the bedside. Should the wearer feel the onset of an attack, he can note the time and this information can then be used in conjunction with the air quality data (gathered every two minutes by the sensor system) to figure out what's triggering it.
Because the vest is attached to the wearer, it tracks the air quality as the person moves through their home, their school, their workplace, or their commute. The researchers, Charlene Bayer, Robert Hendry, and Luis Somoza, want to expand the study and shrink the size of the sensor system from its present <1 lb. Ultimately, they'd like to use it for population studies of asthmatic children. As Bayer says in the news article, "With this system we can determine what children are exposed to at home, at school and outside where they play. Chances are there are some overreaching compounds that seem to trigger asthma attacks in more children."