Scientists have developed a new line of portable, handheld pollution sensors that can allow users to monitor air quality, giving people with asthma and other chronic conditions a practical new tool to keep themselves safe from life-threatening pollutants.
Computer scientists at the University of California-San Diego who created the “CitiSense” device said it is the only air-quality monitoring system that can deliver real-time data to users' cellphones and home computers. The device’s inventors said they can envision one day soon when such monitors could be built into cellphones.
The sensors detect smog (ozone), nitrogen dioxide, and carbon monoxide, and use a color-coded scale for air quality based on the federal air quality ratings — from green (good) to purple (hazardous).
To test the devices, researchers had 30 UCSD students, staff, and faculty members use them for four weeks. The results, presented at the Wireless Health 2012 conference in San Diego this year, showed air pollution can be highly concentrated in “hot spots” — along main roads and at major intersections — or during rush hour, even when air quality is deemed “good.”

By deploying such devices more widely — by putting them in the hands of just 100 users in a metropolitan area, for instance — researchers said they could generate a wealth of useful information about air quality that goes well beyond what the current small number of air-quality monitoring stations now provide. For example, San Diego County has 3.1 million residents, 4,000 square miles — and only about 10 stations.
The goal is to build and deploy a wireless network of small environmental sensors carried by the public to provide information for analysis. Researchers also suggested the devices — which now cost about $1,000 each, but are expected to cost less in the future — could be used to determine air quality trends that might inform strategies designed to reduce exposure risks to asthmatics and others with chronic lung conditions.
"We want to get more data and better data, which we can provide to the public," said William Griswold, a computer science professor at the Jacobs School of Engineering at UCSD and the lead investigator on the project. "We are making the invisible visible."
The CitiSense research was funded, in part, by the National Science Foundation and Qualcomm Inc.