Air flow goes down the cowl, into the CAF, and then into the blower.

So airflow arrow always goes down.

 

Yep arrow doesn't meant "up" it means "flow direction".....always down for cabin air filter.

 

Where ever the blower/fan is, is down. The filter will always filter any debris going towards a mechanical part.

 

The tray is pointed up. The filter direction is pointed down towards the fan

 

Good thing I paid attention to the OEM filters positioning when I swapped it out for a charcoal carbon version.

 

My Venza is 2.5 years old with 17K miles & the cabin filter looked as clean as the new one I installed!

 

It all depends if you park your car in a garage and also near tress. I have a garage and no trees and my filter also looks pretty good for two years old.