How to fix a rupturing wall bathroom tile?
It appears that your wall is failing. Whatever those tile are, they weren't intended for bathroom use. You can scrap off the loose particles and then apply a thin layer of caulk or sealer to the area to prevent you from inhaling the dust. How many tiles you're taking about. Other than that, you're going to have to plan on redoing the walls. The tiles will probably continue to fail even if you improve the ventilation.