In general, does air recirculated in the cabin (i.e. when the re-circulate button is engaged on the dash) pass again through the cabin air filter?
I know that the cabin air filter filters outside air before it enters the passenger space, but is it also used in closed re-circulation?
Specifically: I have a 2006 Honda Civic which only has 1 filter. Am I re-filtering the air as I'm running it on re-circulate mode?
While I'd like to think the air is getting continually filtered, I also don't think it's a good idea to pass cabin air back over all the leaves and pollen and crap the filter took out in the first place, probably makes things worse.
The filter I changed was in the glove box and it had leaves and twigs and all kinds of stuff in it, so I know it is filtering outside air. It seems counter-intuitive to send inside air back over all the garbage in the filter.