Scientists from the University of California, San Diego have developed small, transportable sensors which allow users to access real-time measurements of air quality on their phones.
The CitiSense devices measure air concentrations of ozone, nitrogen dioxide and carbon monoxide concentrations. These are common pollutants emitted by trucks and cars, and are thought to exacerbate asthma. This data is displayed on smart phones as a colour-coded scale ranging from green (least polluted) to purple (most polluted). Estimates of air pollution at other locations nearby can be calculated, allowing people without sensors to access air quality readings.
30 volunteers trialled the devices. Using the sensors, they noticed variations in pollution levels at different times of day and pollution “hotspots” in unexpected areas such as bike paths. The sensors allowed people to modify their lifestyle to reduce exposure to high levels of pollutants, for example by modifying their route to work. The system also facilitated information sharing about air quality in the area between friends and relatives of those carrying the sensors, but also with strangers who were curious about the devices.
The success of the sensors was reliant upon a recent breakthrough made by Sanjoy Dasgupta’s research group at the Jacobs School of Engineering in San Diego. It allowed the removal of noise from data. This means that reliable measurements can be obtained in a variable, uncontrolled environment.
Just 100 of these sensors distributed throughout a large city such as San Diego could provide much more extensive air quality data than currently available. Now researchers are trialling the sensors in nearby San Ysidro, an area known for high levels of pollution. The ultimate aim is to develop a large network of sensors which all send information to a central point to be analysed and made publicly accessible.
