Map LRPA conversion help

The help for the LRPA conversion has a hyperlink for “study of the PA sensors” which results in a page not found error. Does anyone have a correct link for this? I’d link to read about how to implement this correction in my code.

According to

LRAPA has discontinued its own conversion in preference to the US EPA conversion.
The old conversion was, in pseudocode:

IF (pm <= 65) THEN MAX(((0.5 * pm) - 0.66), 0) 
ELSE pm 

Doug, thank you so much for taking the time to reply. This is very helpful.