Interpreting the Purple Air numbers is tricky. I don't know enough about the conversions offered to know what to make of them.
Looking at the weather tower by Lawrence Berkeley Lab, unadjusted PM2.5 gives an AQI of 332. If you apply AQ&U conversion, you get 272. If you apply LRAPA conversion, you get 195. Problem solved. Play ball. On the other hand, if you look at PM10, the unadjusted reading is lowest at 330 AQI.
Most of the lower readings in the Berkeley hills are indoors. You have to unselect the indoor sensors every time you refresh or change settings.
Looking at the weather tower by Lawrence Berkeley Lab, unadjusted PM2.5 gives an AQI of 332. If you apply AQ&U conversion, you get 272. If you apply LRAPA conversion, you get 195. Problem solved. Play ball. On the other hand, if you look at PM10, the unadjusted reading is lowest at 330 AQI.
Most of the lower readings in the Berkeley hills are indoors. You have to unselect the indoor sensors every time you refresh or change settings.