The stagnant air is most likely mildew on the A/C evaporator core, air blows through the core and will pick up an odor.
To help cut down >1998 explorer, 93,000 km.
When running the airconditioner this summer, I am noticing a stagnant
>air type-of-smell coming through for 5 to 10 minutes. This usually
>disipates but it seems to be taking longer and longer to clear.
>The airconditioner was last serviced at 50,000 km. It is coming up on
>another major service shedule at 100,000 km.
>Do you think that's all that will be needed to clear this problem?
>Anything in particular I should ask the service manager?
>Or is it something else?
>A lesser, secondary problem has always been the drawing in of other
>vehicles exhaust odors [particularly those I'm 'following' on the
>road] whether through normal use of fan/venting or using the
>airconditoner. Sometimes I have had to completely turn the air vent to
>'off' when coming up on diesel vehicles or cars burning oil.
>Is that the average for other Explorer owners?