I am working on using the ISAM module in CMAQv5.3.1 for estimating the relative contribution of each specific source category on a severe wildfire event over California this year. However, as noted in the CMAQv5.3.1 issue notes, current ISAM incorporated in CMAQv5.3.1 has overestimated the boundary contribution and the new ISAM module is under development. Therefore, I would like to know when the new ISAM will be released.
CMAQv5.3.2 was released in Oct. 2020, shortly after you asked this question.
I apologize for the late reply.