There're article on internet "try yahoo" regarding this "Air Con smell", it happen not just to our corolla, but most cars.....it has to do with mould & germs in the air con system. Aust. Corolla doesn't come with the filter as far as i know, I think they have it for the Jap local one. I put a piece of Activated Carbon Filter bought from the local aquarim last week. It seems helping a bit, but it's still early to tell...but the down side is it lowered the fan power. I knew there was a company that sell those "activated carbon filter" for home air con on the internet, but I can't find it on yahoo anymore. If anyone find one, please tell us. I think that would help lot better :) By the way, from one of the article i read, if you turn off the air con 2 mins before you arrive your destination, that would help dry up the moisture in the air con unit, and reduce the chance of having the mould and germs to grow in the unit. Hope this help.