Troubleshooting the alarm when PM2.5 mass concentration above expected bound

How to diagnose and resolve issues causing PM2.5 mass concentration measurements above the expected bound.

This alarm indicates that at least 25% of the readings in the last three-hour period of the device’s raw PM2.5 mass readings are higher than expected (above 3,000 µg/m³), which may indicate a sensor malfunction. If you see this alarm, there are a few things you should troubleshoot.


This alarm may indicate that something (typically a bug or spider web) is stuck inside of the sensor. Typically if this is the case, the Node will show raw PM2.5 mass concentration values much higher than surrounding Nodes, and/or PM2.5 mass concentration levels from the Node will appear “stuck” to very high or very low levels. Use Analytics > Explore to check the latest PM2.5 mass concentration readings from the Node.

Example of a sensor with a blockage.


If something is stuck inside the sensor, try clearing the blockage by following these steps.


If these steps are not resolving the issue or if you have questions, please contact our Support team and we will get back to you shortly.