Checking of Remarkably High Values

I often see sensor #57231 showing > 600 PM10 values, which I find remarkably high for that location in Switzerland. I suppose it’s just possible that the local flooring company location is really putting that much PM in the air, but I very much doubt it.

Do such values ever get queried by Sensor.Community? Maybe the submitter has a problem with their sensor? Or maybe they really are living in such a dangerous situation? In either case, does an email get sent out to question such outlier values?

It is basically an issue. We promised never to send any Email and we never do (except for the automatic Email for deconnection). The user has to take care of its own sensor… Or maybe he smokes every hour next to the sensor…
But I thought we had implemented to filter sensors in such a situation.

This is just a casual observation, but I noticed that (heavily) malfunctioning sensors tend to show measurements as a flatline and ovelapping pm2.5 and pm10 values. I would bet that it is close to some emission source. Although that’s problematic in itself.

Or maybe it’s an indoor sensor which is falsely declared as outdoor sensor? I had to learn that indoor sensors are not displayed at the map, which means, that there is some wrong incentive to delare indoor as outdoor sensors, if you want it displayed.

By the way, just to change this wrong incentive I would suggest to display indoor sensors, too, but with a marking as indoor sensor. I understand the problem with that, as it is a costly help displaying only private data, but I would still vote for displaying marked indoor sensors.

Thanks to everybody!

P.S.: I myself don’t have a problem with that. I have an declared indoor sensor anddon’t need it displayed on the map. I am not talking about my personal interest.

I am still not sure about the conditions. Please check @pjg and @bertrik answers in my post: display-sensor-on-map-sensor-community-and-using-an-air-quality-lamp-from-the-project-stofananas-together-with-a-sensor

Maybe you could add an option in the T&Cs to be informed when the air conditions are looking dangerous. Personally I would like to know if I should avoid breathing. Or if my sensor has developed a fault.

You Mean this?
Screen Shot 2023-09-27 at 19.39.52
I do some advertisement :slight_smile:

It is a project in Marseille code is opensource:

By curiosity I wanted to check this sensor as I noticed on some sensors specific spikes in particular in winter.
Surprisingly the output levels of this sensor are not usual and quite high and apparently not realistic.
It is sure not an indoor sensor as we have for an indoor sensor sometimes high spikes compared to a medium value. The medium value is quite higher than any sensor located on a motorway. This sensor seems to have an anomaly with an offset on the output signal and/or an excessive gain by a factor of 10 to 20. Breathing such values, you should be today at the hospital !
Nevertheless, the SDS011 sensor showing a good dynamical response, the environnement of this sensor is quite disturbed as there is no real quite period with a stable environnement; it is worth to check this with another sensor in the vicinity of this one; any strong disturbance is usually also seen in a neighborhood of several hundred meters.

Oddly the sensor in question appears to have now disappeared. Coincidence?

What is strange, the sensor does not appear on the community map with the declared coordinates (long/lat) but continues (Jan 2024) to transmit the same unrealistic data.
Is there a way to identify the position of a sensor through its ID number? Or does it disappear from the map through a tricky configuration?

You can find the position with the MAP ID.
Send it here and try to find out the date the sensor emitted for the Last time. I will then be able to check

Thank you. I did not know this option.
Indeed the sensor has been recording until the 7th of January and today is disconnected. It took a long time, more than a year, to realize that the sensor was not operating properly with spikes up to 1000 micro g/m3 during several hours.

I have a couple of very low values due due an defect of the sensor.

Is it possible to delete that data with -°C ?


First anomaly is your RH sensor which is most of the time saturated at 100% whereas your PM measurements are correct i.e not showing humidity effect (like fog with water drops).
Presently your temperature sensor gives realistic values; spikes above 15°C only show that it was a sunny day and your sensor is exposed to sun at some hours. However you may need to correct the recorded value as the temperature sensors are not calibrated and are usually affected by an offset; you can correct this offset (at your level) by comparing the measure with an other official temperature sensor, for instance by checking on internet the data with an official meteo station.
The fact that in August you had very low values (always -144°C) demonstrates that the sensor had a problem (probably not at the sensor itself as the anomaly did not appear again and the sensor seems to work correctly now) but submitted to disturbances at transmission level (?) showing like a saturation as your RH sensor is presently showing. The only way to delete this wrong information is to put some thresholds (low and high) representative of unrealistic values when you are doing a treatment of your sensor data allowing to detect unrealistic values and killing them.

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