Smartphone pollution monitor could benefit asthma sufferers

The inventors of a new smartphone-based pollution sensor say it could help asthma sufferers avoid exposure to pollutants.

The computer scientists from the University of California, San Diego, claim their CitiSense technology is the only air-quality monitoring system that can deliver real-time information about pollution to phones and computers at any time.

Data from the sensors could also be used to estimate air quality throughout the area where the devices are deployed and made available to everyone through the internet, not just those carrying sensors.

‘We want to get more data and better data, which we can provide to the public,’ said lead investigator Prof William Griswold in a statement. ‘We are making the invisible visible.’

The researchers say 100 of the sensors deployed in a fairly large area could generate much more data that a small number of air-quality monitoring stations required by the US Environmental Protection Agency (EPA) can provide.

For example, San Diego County has 3.1 million residents living in a 4,000-square-mile area but only about 10 monitoring stations.

/p/p/e/TE_SanDiego_pollution_sensor2.jpg
Inside the CitiSense sensor, three cylindrical components detect ozone, nitrogen dioxide and carbon monoxide

The CitiSense sensors detect ozone, nitrogen dioxide and carbon monoxide — the most common pollutants emitted by cars and trucks.

The user interface displays the sensor’s readings on a smartphone by using a colour-coded scale for air quality based on the EPA’s air-quality ratings, from green (good) to purple (hazardous).

To test the sensors, researchers gave them to 30 users for four weeks, who found that pollution in their areas remained concentrated in hot spots along main roads and at junctions, rather than diffusing evenly through the air.

They also found that users were far less exposed to pollution when in their cars. ‘The people who are doing the most to reduce emissions, by biking or taking the bus, were the people who experienced the highest levels of exposure to pollutants,’ said Griswold.

/p/p/e/TE_SanDiego_pollution_sensor2.jpg
The CitiSense sensor can be worn on a backpack

The CitiSense technology could be built into smartphones, allowing large numbers of people to keep monitoring pollution and potentially take action to limit their exposure, the researchers said.

In the study, for example, cyclists were able to avoid a great deal of exposure by riding one block away from a busy street. One user convinced his supervisor to install new air filters in the office after registering poor air-quality readings on his sensor.

The sensors currently cost $1,000 (£617) each but the researchers believe they could easily be mass-produced at an affordable price.