In that climate, I suspect that it is not only the airport shuttles that have this problem. On other islands we travelled to, and in places we stayed in SXM, the condition of the air conditioning units/vents left much to be desired. For most of the years we travelled south, I packed a can or two of Lysol disinfectant spray and doused the air conditioner and other spots in the room.

In one place that we stayed (it shall remain nameless) the AC was so bad my husband purposely disabled it to force the hotel to move us to a better, healthier room.