There’s a new kind of filter in cars and trucks today and you may not know about it.  It’s the filter that cleans the outside air before it gets pulled into your cabin by a ventilation fan.  This paper-based filter prevents pollen, dust and other airborne particles from entering.  If you, or a passenger, have any allergies, this filter can provide quite a bit of relief from airborne irritants. Most automotive manufacturers suggest that your change your cabin air filter every 10,000 to 15,000 miles in standard environments.  Perhaps more often depending on where you drive – especially if you drive in urban environments with poor air quality or in desert climates with lots of dust. You may be able to do this yourself.  Many cabin air filters are located behind the glove box.  Often, they can be accessed by dropping the glove box from its support fasteners.  In other vehicles, the cabin air filter may be under the dashboard and might not be so easy to reach.  In this case, you might want your car dealer to perform the job for you. By the way, you may be surprised at how expensive a replacement cabin air filter is.  These are relatively large affairs and are made of ultra-fine paper or filter material.  They are typically twice or more expensive than common engine air filters which don’t have to catch miniscule particles such as fine dust and pollen. If you elect to have your dealership, replace your filter, ask to see it before they toss it.  You might be surprised to see that stuff that it has caught.  It may have insects, leaves, dirt and all sorts of stuff attached to its surface.  When you see this sort of debris, it becomes pretty obvious why having a cabin air filter is such a good idea. Source: