Well you seem to be the expert enlighten me, lights is not defined by radiation either, uv rays are radation, and our ozone stops i belive 98% of that radiation. so if you can get skin cancer from 2% of the uv light that makes it to earth, im sure that any one who makes and distributes lights knows what leveles to use. Your talking about radiation that in the buisness world is taken very seriously and is of standards on all lights. nanometers in Par calculates for the difrent kinds of light that you can and cannot see, such as infrared. this can be understood in simpler terms as light color. So to answer your question you wold be looking for 550 to 700nm PAR (Red Spectrum).