German scientists at the Karlsruhe Institute of Technology are developing a new sensor that attaches to a smartphone and measures particulate matter (fine dust) levels in the air to draw up a pollution map.
The principle of fine dust measurements using a smartphone corresponds to that of simple optical sensors. The smartphones sensor can measure concentrations of about one microgramme per cubic meter and is sufficient for detecting coarse dust and smoke, but not for typical fine dust concentrations in the microgramme range.
The sensor is planned to be attached to the smartphone by means of a magnet and the users take a photo or a video for measurement. Users can join a participatory sensing and download the corresponding app. The images can be evaluated locally or transmitted to a computer system that combines these data with other measurements and sends them back. Then, the fine dust concentration is displayed by the phone.
"Instead of the conventional infrared LED in the sensor, the flashlight of the smartphone emits light into the measurement area. This light is scattered by the possibly existing dust or smoke," said computer scientist Matthias Budde.
"The camera serves as a receptor and takes a picture representing the measurement result. The brightness of the pixels can then be converted into the dust concentration," said Budde, who developed the system as a member of the research group TECO of Karlsruhe Institute of Technology (KIT)'s Chair for Pervasive Computing.
Fine dust pollution can cause health problems, but it is difficult to accurately track its concentration across cities and regions. The new sensor would be able to use the aggregated data to generate pollution maps. Lead researcher Matthias Budde stated, that how many people will be needed to make a reliable map is yet to be determined as the sensor is still being developed and has not been properly field tested.
"The more stable and accurate the employed sensor is by itself, the more meaningful individual measurements become and the less important is the density of the measurements," he says.
Source: Phys.org
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