Air Gradient Indoor Monitor Fails to Detect Varnish Fumes

My house is undergoing renovations and they are currently putting varnish on the cabinets. The smell is nauseating and has spread throughout the whole house. The problem is that none of the sensors on my I-9PSL seem to detect poor air quality. Is there a problem with the sensors? I have trouble believing it’s safe as even the workers are wearing respirators.

You should definitely see some spikes. Can you please contact our support through our website and then we will have a closer look at the data and could even have a zoom call to discuss.

I have found the problem. The sensor is completely relying on an index that is too reactive. Here is a picture of the TVOC levels during the day with relevant explanations.

Yes, this is the expected behavior. You can read more about it here:
TVOC - When it's useful and when it's useless

Also, in the next fw release you will be able to adjust the time it takes to recalibrate to 100. It is called “Learning Time Offset Duration”

Here is a preview of the new feature.


But in this case, I wanted to know when it was safe to reenter the bedroom, and having the sensor recalibrate when the TVOC levels were very high made this impossible. I should be able to manually set the baseline, as is typically done in sensors with manual calibration.

I believe the baseline is set after a power cycle and then should be around index 100. I will check if we can also trigger this by the software.

Yes from testing the device the baseline resets every time the monitor is unplugged. If I wanted to keep the baseline from auto calibrating away from a desired value (the one acquired on boot up), should the index learning time offset duration be closer to 12 hours or 720 hours?

You should put it to 720h and then it should take a very long time for it to autocalibrate. Please note that you need to install the latest firmware for this feature (Version 3.1.1). Also, this is a completely new feature and we are still testing it so there is a risk that it does not yet work as expected.

Do you know where I can modify the setting? I can’t find it.

@Achim_AirGradient Do you know where I can put it to 720h?

I just see that the feature seem to be not yet deployed to our production server. I will ask our developers to get it deployed asap.

It should now be visible here:

Make sure you wait for the update button at the bottom to make sure you have the latest version.

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