Hi Airboy,
Thanks for engaging in this discussion in our community! I wanted to share some information from our end to provide clarity.
There haven’t been any changes to our system or algorithms - the data you’re seeing is being reported the same way from the sensors as it has always been.
These low readings can happen naturally. An AQI of 0 isn’t necessarily erroneous; there are plenty of areas with very clean air, particularly around this period of time that you’ve indicated.
If you want more granular detail on the air quality, you can look at other data layers on our map for information such as particle counts (I’d recommend the 0.3 micron particle count data layer for most visibility). You can use our map guide for some assistance in navigating these data layers if needed: PurpleAir Map Guide.
If you or anyone you know has the chance to go outside when the air looks like this, we expect that you’ll see a beautiful spring day.
If there is any particular sensor that you’re concerned is reporting erroneous data, we can certainly take a look at it. If you have any other questions or concerns, feel free to let us know. You can reach out to us at contact@purpleair.com as well.