Shoo bug

A friend of mine in the hotel business tells me that his job is pest control. They have a schedule in which sections of the building are sprayed , cleaned and deodorised. They regulate the occupancy so that the guests are minimally exposed to the smelly stuff, but he has to handle pesticides routinely and is worried about the long term impact on his health.

I remember reading somewhere in the halfbakery about this cone-like thing that emits ultrasound and keeps the bugs away (In UB's kitchen?). Something of that sort should be employed in buildings, to minimise use of poisons.

All hotel rooms are painted with piezoelectric paints. When the room is unoccupied, the walls are energised with high power high frequency voltage so that a large sound pressure level is created in the room, large enough to kill any marauding bugs. This is scheduled just before the cleaning gang is due to visit, so that the bodies do not lie around attracting more bugs.

Energising the walls at a low level, continuously, to repel insects, might not be an option since guests might have their pe(s)ts with them, for instance a canary in a cage and a cat though may be not the latter if the guest is eighth.