For what it’s worth, purpleair sensors have a local API to retrieve data directly, without going through their cloud service or web site. It’s documented at Sensor JSON Documentation . I use this for my own local dashboard, and haven’t seen any discrepancies with what’s being shown on the website, either EPA or Purpleair - it’s just been beautiful spring weather with low (but not zero) AQI’s, which is normal here.
One thing to be somewhat wary of these days is there’s many voices out there on the internet trying to panic you to increase your engagement with their sites, or to push their own agendas.