Mobile phone-based air pollution detector: developed from Germany

In any more or less large industrial city and its surroundings, the air is polluted with a large number of suspended particles. And these are, for the most part, third-party substances with which the industry works, plus other man-made components, decay products formed during combustion and all the rest.

In general, all this is very unhealthy, and in some cities people even have to wear face masks, in the case of a particularly active production phase and a certain configuration of the wind rose.
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An assessment of air quality in such places is, of course, carried out, but by no means in all regions and not as often as we would like. The reason is the high cost of the analysis and the need to use regular and mobile laboratories. The other day, German scientists from the Karlsruhe Institute of Technology offered their solution .

This solution is a small mobile phone module that measures air quality using a camera and a flash device. Of course, using the module on a phone without a camera and without a flash will not work.

The module itself is fixed on the back of the smartphone using a magnet, with the module holes should be located above the flash and the camera of the smartphone.

Everything works quite simply. A person presses the “take a photo” button (having set the flash mode), the flash fires, and the light from it goes through the optical fiber to the camera sensor.



There is also a passive air intake in the module, through which the light from the flash passes, before reaching the camera lens. The more suspended particles in an air sample taken, the more light is scattered.

For their module (its case, by the way, printed on a 3D printer), scientists developed a corresponding application that analyzes the images received by the camera, calculating the number of particles in the air from the brightness of the pixels in the resulting image. According to experts, the brightness of the pixels in the photo allows you to quite accurately calculate air pollution, for which a special algorithm was developed.



After testing their instrument, scientists compared their own results of atmospheric research with the results of studies of standard air quality stations. The results came together fairly accurately.

Of course, the device has its limitations. In particular, it can capture atmospheric pollution at a concentration of suspended particles up to about 1 milligram per cubic meter. In addition, particles less than 10 microns (and the fine fraction of dust is the most dangerous, by the way) are also not fixed by the instrument.

Now scientists are engaged in improving the characteristics of the device so that it is possible to take into account the fine fraction of dust.

According to the developers, their device can be useful to all people, users of mobile devices who are concerned about the quality of the atmosphere of their city. Using such a device and its application it would be possible to quickly draw up a map of the pollution of the atmosphere of a city / region, after which the results would be provided to the appropriate services.



Article scientists available in .pdf here .

Via mobihealthnews