I think there are actually three important factors when it comes to aerosols:
1. HVAC system
2. Room cleaning
3. Former guests
I’d worry more about 2. than about 3., because in most cases room cleaning is more recent (higher prob of aerosols in the air) and it’s hard work, leading to heavy breathing.
To some extent 1 and 2&3 could go into different directions—a HVAC system shortening the time a problematic amount of aerosols is airborne but possibly (depending on the system) leading to the the risk of getting aerosols from other rooms.
I would guess the safest thing would be (if that’s possible in you location):
1 Hotel room without AC, just with ventilation for the bathroom.
2 Ventilating the room before taking of the mask and/or going outside for some amount of time after getting the room (so that the amount of aerosol, primarily from room cleaning, is reduced). Especially if you are early or you see signs of very recent cleaning (e.g. wet surfaces).
Unfortunately, I am not able to quantify the risk.
I think there are actually three important factors when it comes to aerosols:
1. HVAC system
2. Room cleaning
3. Former guests
I’d worry more about 2. than about 3., because in most cases room cleaning is more recent (higher prob of aerosols in the air) and it’s hard work, leading to heavy breathing.
To some extent 1 and 2&3 could go into different directions—a HVAC system shortening the time a problematic amount of aerosols is airborne but possibly (depending on the system) leading to the the risk of getting aerosols from other rooms.
I would guess the safest thing would be (if that’s possible in you location):
1 Hotel room without AC, just with ventilation for the bathroom.
2 Ventilating the room before taking of the mask and/or going outside for some amount of time after getting the room (so that the amount of aerosol, primarily from room cleaning, is reduced). Especially if you are early or you see signs of very recent cleaning (e.g. wet surfaces).
Unfortunately, I am not able to quantify the risk.