PurpleAir sensors are not appropriate to use as a reference sensor. There is too much interference from Plantower’s “adjustments”. If anything, you’d use the Temtop to create adjustment curves for the PurpleAir, as the responsiveness characteristics of the Temtop are (likely) published by the manufacturer and that can be used to create the K factor(s) to adjust it to a reference source (FRM/FEM or whatever is appropriate for your environment).
I’d recommend reviewing the papers posted in Lance’s thread, linked below, to understand the procedure.