CVO 10/7/2012For air quality .
Ed 10/8/2012Gee thanks. That clears it up.
HouseCallAuto 10/8/2012My answer is just "my own opinion". They are expensive because they can get away with it. After all, protecting the air that a human breathes almost qualifies as a medical device, whereas filtering the air that an engine breathes (the simple air filter) carries no responsibility really. I would bet they both cost equal m oney to manufacture but since the cabin filter would sell in somewhat limited quantities compared to engine air filters, they will get a premium.