Pontiac 2008 G5 Owner's Manual page 140

3. Open the passenger compartment air filter door by
reaching through the opening in the back of the
glove box and raising the tab until the door can be
opened downward.
3-24
4. Remove the filter by sliding it out of the housing.
When installing a new air filter make sure the
AIR FLOW arrow is pointing downward. Reverse
Steps 1 through 5 making sure the glove box door
goes back into place.