Er, I'm a bit confused about this: It is important to note that it is very dangerous to try to use this method to disinfect surfaces inside homes. To be fully

Er, I'm a bit confused about this: It is important to note that it is very dangerous to try to use this method to disinfect surfaces inside homes. To be fully effective, a system must be designed so that a person is not directly exposed to the light. Does this mean that the proposed system should be used for only situations where no people are present? Say, a bus/train at a terminus rather than in transit, or a hospital ward emptied for the purpose of such disinfection? I am probably misremembering things, but I'd long thought that if you irradiated quite a few things intensely enough, they'd just die off - whether with UV or something harsher. How is this different, other than delivery via (cheaper?) LEDs?