Map dot shows 0, while graph shows > 50 for 24 hours

Map dot shows 0, while graph shows > 50 for 24 hours

Hi! It’s my first time posting here, and I’m hoping someone could help:

The map dot for my outdoor sensor is always showing 0, but when I click on the dot the graph never agrees. However, the values on the graph for my sensor agree with the values showing on other map dots in the area. So my sensor seems to be working fine, and apparently the only problem is the value showing on the map dot. See the enclosed screenshot where the map dot shows zero, but the graph shows it has been over 50 for more than 24 hours. What’s wrong with my map dot?

I’ve tried removing and re-registering the sensor and whatever I could glean from the websites, but to no avail.

Hopefully this URL will let you see what I’m seeing: Real-Time Air Quality Map | PurpleAir
Please let me know if there’s any other info I could provide to help troubleshot.


Hi @flub1dub, this appears to have been an incorrect downgrade done by our systems. We have corrected the issue by downgrading the appropriate channel, and your device should now report correct readings. However, it will remain transparent to indicate that a channel has been downgraded.

Your device has two laser counters that conduct independent measurements. These are referred to as “Channel A” and “Channel B”. Channel B for your device is reading correctly as seen in the map graph. However, Channel A appears to be reading only zero. If you hover your mouse near the bottom of the graph you’ll see the data for Channel A highlighted.

If a channel isn’t reporting correct data, it can be “downgraded” by us to prevent the bad data from showing on the map. In this case, Channel B was downgraded by our systems when Channel A was the one producing bad data by reporting all zeros.

The zero readings are likely due to a broken fan, but could also be caused by debris. For information on cleaning your device, we recommend you take a look at our sensor maintenance article. If cleaning does not resolve the issue, your device may need replacement laser counters.

If Channel A begins to read correctly again, please contact us and we can remove the downgrade.

1 Like

It’s possible the website is simply wrong. It can’t be zero, not for 24 hours. Air is never THAT clean. It’s likely some site issue.

Thank you very much @Josh_PurpleAir!! Your response is better than I hoped for!

1 Like

I cleaned my sensor, and now channel A is tracking channel B, albeit with lower readings. Thanks again so much for the advice!
@Josh_PurpleAir is my channel A good enough to be upgraded now?

1 Like

@flub1dub, we’re glad to see that your device is reading properly! The downgrade on channel A has been removed, so your device will now show an average of the two channels on the map.