Humidity is in the 40-60range. Late flower and harvest. maybe 20x20+ canopy or dry space. Room is just a large open space.
The ac unit is a separate dual hose unit. Sort of near it I have my filter… “filter > Inline fan > duct > out”. The filter is thoroughly duct taped to the inline/ducting. (Probably not the most efficient placement as I’m pulling some ac air out. Need to change that in the future.)
@Heliosphear - are you saying it’s highly probably that it could be the ac unit? These types of units are not supposed to exchange air out of the room… I’m not too sure, still have not ruled it out. (I do have two ac units opposite sides of the room and am noticing smell near both.)