Not a bad idea, although it is out of my technical knowledge range. I am sure someone on CPF would know. I do not believe UV in general has much penetrating abilities. I believe most water UV systems pass a narrow stream of water pass the UV light and are sealed to prevent any dust from collecting on the UV tube.

I also know, based upon my lab experience here at Ft. Detrick, that most UV systems in biological hoods, must have the bulb cleaned almost cleaned daily (to be truly effective) with alcohol, since even a thin layer of dust can effective the efficacies of the UV rays in killing organisms. Left over from Ft. Detrick’s biological warfare days, many of the buildings that were converted to cancer research labs, had pass-through areas with UV lights completely surrounding the room, in addition the rooms were painted with an aluminized paint in an attempt to bounce back some of the rays. Most of these have been found to be relatively ineffective and in most areas they have been removed or decommissioned.

Pete