PurpleAir PA-II and PA-II-SD sensors contain two laser particle counters that measure real-time particulate matter and report as Channel A and Channel B.
If one of the channels appears to be reading improperly, it can be downgraded. A channel can be downgraded automatically by our systems, manually by PurpleAir staff, or by the sensor’s owner. A downgraded channel will not be used in its sensor’s data average and will lower its sensor’s confidence score.
You can tell which channel is downgraded by clicking on a sensor’s map marker.
Downgrade or Restore a Channel Yourself
If you’re the sensor’s owner, you can downgrade a channel that’s reading incorrectly, or restore a channel that was downgraded incorrectly:
- Sign in at purpleair.com with the Google or Google Workspace account that matches the sensor’s Owner’s Email.
- Open My Sensors from your profile icon.
- Open that sensor’s Details.
- Choose Downgrade Channel or Restore Channel for Channel A or Channel B.
A manual downgrade stays in place until it is restored. It doesn’t clear on its own when the readings return to normal. If you’ve cleaned or replaced a laser counter, restore that channel once its readings look normal again.
These options appear only for the sensor’s Owner’s Email. An Associated Email alone doesn’t show them. If you can’t sign in with the Owner’s Email or need it changed to a Google one, send an email to contact@purpleair.com for assistance.
Learn more about channels reporting high, not working, or spikes erratically.
Learn more about sensor maintenance.