In an office building located in Mexico City (a location with a high PM2.5 and ozone levels), the floors are served by AHU’s equipped with MERV 8 filters. ASHRAE 62.1-2010 requires to have MERV 11, which is not feasible because the fans cannot overcome the increase of friction losses. Has anyone faced this problem? Can we somehow skip the requirement of MERV11 filters?

The replacement of AHU isn't possible because they would need to remove part of the exterior wall of the building in order to be able to remove the equipment and introduce a new one.