GM, in their overtime-penny-pinching wisdom, left the cabin air intake (this is what goes through your heater, and your AC) open in the 2006-2013 Impala.

It’s nearly directly exposed to the weather. This cover (which was not designed to be completely watertight) will not keep water from pooling on the filter (which may mold- certainly will annoy allergies), so they decided to stick another piece of plastic over the filter itself- beneath the now-top cover to assist with mold prevention. It does nothing to prevent the filter from getting wet, except for ‘dribble through’ prevention. What about other allergens, such as dust?

The pictured filters were new in 2014. Obviously an open-exposed filter will degrade faster- but this is the worst “not original” filter I’ve seen in a car that didn’t have something BROKEN in order for the dirt to get to it. It’s always a good plan to replace these yearly- more often if you are in a harsh climate. This is still no excuse for poor design.