One available option when buying a new Forester (at least in 2003) is to get one with an in cabin airfilter. The filter minimizes the dust, pollen, and other road contaminates that you breathe in while driving. It keeps the air you breathe a little cleaner.
If you don't get one with a new car though, you can add it your self. The filters can be found on line for $20-$40. To install it, you just take off the glove compartment and put the filer inside.
Here is the what the filer looks like.
To take off the glove compartment, you need a Phillips screwdriver. The instructions tell you to find and remove 9 screws.
Three are on in the upper left of the open glove compartment.
Note that too of the are on the outside frame of the glve compartment, and one is inside on the upper left of the back wall.
Three are in the upper right in similar positions.
One is in the center behind the latch.
The final two are harder to see. The are on the bottom of the glove comartment. You may find it easier to look for them by looking for the screw drive tracks.
(The rusty metal piece is my screwdriver.)
With all nine screws removed, the glove compartment should just wiggle out.
Be careful not to break any of the clips or bits of plastic. They will help you align it when you put it back in later.
Now the instructions tell you to remove the plastic cover from the housing.
They don't really tell you how, though.
First of all, you are done removing screws. There are two small ones that look like they hold the cover in place, but actually the don't.
Look for the two plastic tabs on the air filter cover. They are parallel to the ground.
One is on the left.
One is on the right.
Apply gentle upward pressure to those tabs to release the filer cover. It should come right off.
Now just slip the new filter in. Make sure the up arrow points up. There is no clipping or fastening involved. Just slide it into the hole.
Put the plastic cover back on. Work the righ side into place first, because that can the more challenging side.
Then reinstall the glove comparment and put all nine screws back in.
And, of course, note it on the door frame.
And observe Subaru's final cautions.
And then you are done. Just turn on the AC and wallow in the wonderful odor of Nothing.
If you do the installation, be careful. There are lots of sharp and pointy things inside the dashboard and you could cut or injure your self.
Also, keep in mind that you are working near and explosive charge. Subaru doesn't mention this in the manual, but you are working just inches from the air bag.
So don't go around just poking things with your screwdriver. Which, come to think of it, is probably a good general life lesson, too.