We have purchased 70 Atmotube units from you this fall.
1. NOx sensor readings:
Regardless of air quality, the NOx value consistently remains at 1. The highest value we have observed is 2, and that only very rarely—even in environments with clearly polluted air the value of NOx index is 1.
We would like to understand whether the NOx sensor requires any specific activation, calibration, or warm-up procedure. So far, we have tested approximately 15 units, and all of them exhibit the same issues.
2. PM sensor not reporting values
On several units, the PM sensor initially worked for a short period but then stopped reporting any values. We have tried cleaning the sensor from app, restarting the app, restarting the device, and unpairing/re-pairing the units, but none of these steps resolved the issue. This issue is found in 3 out of 15 devices.
We are planning to distribute these devices to end users soon, so we would appreciate your guidance on how to resolve these problems.
Could you please advise:
Whether these issues are known?
If a firmware update could address them?
Or if there are any recommended troubleshooting or calibration steps?
Thank you for the detailed report. We understand the urgency, especially with an upcoming end-user rollout.
1. NOx sensor readings
The NOx sensor in Atmotube PRO 2 is always active and does not require manual activation or calibration. It is important to note that the NOx Index is a relative indicator, not an absolute concentration value. It reflects changes in NOx levels relative to the sensor’s recent baseline, rather than overall pollution intensity.
If the device operates mostly in environments with consistently elevated NOx, the sensor baseline adapts, and values may remain low (1–2) even in polluted air.
The index increases mainly when there is a sudden rise in NOx compared to recent conditions (vehicle exhaust, gas appliances).
Since you are seeing consistent behavior across ~15 devices, this strongly suggests normal sensor operation rather than a fault.
2. PM sensor not reporting values
To help us investigate whether this is firmware-related or device-specific, could you please clarify a few points for the affected units?
Firmware version
Could you confirm which firmware version is currently installed on the devices with the PM issue?
PM mode setting
In the app, under Settings → Sensors → PM Read Interval, which mode is selected? (e.g., periodic vs continuous)
PM fan operation
When PM measurements are expected, do you hear a quiet fan/ventilator sound from the device? (This sound indicates that the PM sensor is actively sampling air.) Can you hear the fan while the PM clean operation is performed?
Data visibility
For the affected units:
Are PM values missing both in the real-time view and in history, or
Do values appear briefly and then stop updating?
There are currently no user-level calibration steps for the PM sensor beyond what you’ve already tried, so your answers will help us determine next steps and whether a firmware update or device replacement is appropriate.
Once we have this information, we’ll be able to advise you more precisely.
Thank you again for your cooperation — we’re committed to resolving this before your deployment.
One of our testers finally managed to record values of Nox = 4 (walk outside). Also we tested a unit in the lab (experimentally) and got values > 340. So the NOx sensors work. It all depends on the types of cars (now most are modern engines) and air circulation in the area were measurements are performed. So it is perfect!
Concerning the PM values: The values are missing both from real time and also in history. The firmware was the last updated when the devices were paired to the mobile phones. PM interval was set to continuous 1s. I will let you know about if fan/ventilator can be heard.