I visited the panera bread last week there are so many ceiling tiles that look like that have mold? dirt? on them and some are missing there is a large area in the main eating area where there is a pendulum light that looks as if a whole section has been removed or ? there is what looks like raw wood or wood that has been scrapped above the large table there. called Manager and was told they are aware and that it is being worked on and that is all she can do! if this is coming from vents all the more to worry? you may want to consider another place to eat
clean or replace tiles and clean vent system and close open areas
especially now this should not be happening. you are just now trying to reopen!