what does it say,
when crews comment on alledged smells,
but do not follow company procedures for such,
do not complete air quality forms....?
most aircraft can be made affected by smells if operated in a certain way,
contrary to operating procedures.
if problems occur, it'll take rational people to help identify the cause, the more information the better.
certain operators have flown with analysers on aircraft alledged to be problematic,
for no abnormal readings to be found.