If you care about accuracy, my understanding is that the Purpleair is your best choice. I don't care about absolute accuracy, although it seems to agree with

If you care about accuracy, my understanding is that the Purpleair is your best choice. I don't care about absolute accuracy, although it seems to agree within 10% or so with nearby putpleairs. The main reason for a monitor is just to make sure your filtration is working and sized appropriately. Take it outside, take a reading, take it inside, see if it's a lot lower. I don't see a need to spend a lot for this or install something that connects to my wifi and needs to be updated etc.