Thanks a lot for posting that. Has Purple Air been made aware of that finding? I’d like to know what their response is. Actually, mine doesn’t seem to be that far off compared to what AirNow shows for Fremont, CA. Of course, I have no idea exactly where their sensor is. Like right now, my sensor shows 54 AQI and Fremont is showing 59 AQI so, I am under what they are showing.