Those lights (like most lights) give off a broad range of frequencies. The blue / violet parts that humans can see are by definition not "ultra"violet (beyond t

Those lights (like most lights) give off a broad range of frequencies. The blue / violet parts that humans can see are by definition not "ultra"violet (beyond the visible spectrum). Even if we could see those frequencies, not much would be needed to explain it other than it helps us see certain things / under certain conditions better.