Smartphone sensor to monitor air pollution

Scientists at the Karlsruhe Institute of Technology, Germany, are developing a sensor, which attaches to a smartphone to measure particulate matter and fine dust particles in the air.

The basic idea of smartphone-based sensing, was to track the level of pollution by drawing up a pollution map, which could be very helpful in tracking city pollution level, especially in cities like Beijing and New Delhi, with very high levels of smog, according to the report with agency inputs.

Computer scientist Matthias Budde who developed the system as a member of the research group TECO of Karlsruhe Institute of Technology (KIT) told a news agency, instead of the conventional infrared LED in the sensor, the flashlight of the smart-phone emitted light into the measurement area. This light was scattered by the existing dust or smoke.

He added, the camera served as a receptor and took a picture representing the measurement result. He added, the brightness of the pixels could then be converted into the dust concentration.

The smartphone sensors were not yet as precise as specialised instruments, their costs, were however much lower and Budde planned to enhance accuracy by a high measurement density, PTI reported.

Measurements of many, closely adjacent sensors may be combined to results of reduced inaccuracy.

Their close vicinity might also allow the sensors to be calibrated against each other.

According to Budde, a potential application scenario was joint measurement or participatory sensing - interested citizens measured data at various places in their city and shared it.

The data might then be used for drawing up a fine dust pollution map for the respective city in real time.

Users who wanted to join participatory sensing would need to download the corresponding app.

At the desired measurement point, the sensor was attached to the cell phone and the users took a photo or a video for measurement.

The images could be evaluated locally or transmitted to a computer system that combined the data with other measurements and sent them back. The fine dust  concentration was then displayed by the phone.

The smartphone sensor could presently measure concentrations of about one microgramme per cubic metre, which was sufficient for detecting coarse dust and smoke, but not for typical fine dust concentrations in the microgramme range.