PurpleAir has some fairly inflated numbers compared to AirNow, which is the EPA's gold standard. That said, PurpleAir can give a better idea where the really localized poor air quality is. When AirNow was reporting 260, PurpleAir was reporting numbers over 400, sometimes as high as 497, which I think people just start dropping like flies if they breathe that in. Use both to get the full picture.
It was crazy, it sort of hooked right around your area and nailed us. Starting to smell like campfire again.