i just found out last fall, that the Sonata I owned from Aug 2001-Feb 2010, and put about 100,000 miles on, had a cabin filter.In most cases, folks do not even know that their car has a cabin filter. My friend kept telling me, I change the air filter regularly until I pull the cabin filter
Check for a recall on the AC odor. The vehicle might be young enough.I just bought a 5 yr old MB ML350 with 37k on it. Noticed the ac smelling like a dirty vacuum cleaner bag. Sure enough it had never been changed. And the vehicle has 3 filters. It still smells with new filters so next step is to clean the heater/ac core.
The air filter also had never been changed but it is a pita to check or change and I think the car has a monitor that signals when it's totally clogged.LOL