Hello, the book sterilizer adopts the principle of ultraviolet sterilization. General books are easily polluted by various germs in the circulation process. So some libraries will use an ultraviolet sterilizer to quickly kill bacteria, viruses, dust and so on for 30 seconds at a time. There is generally no polluting radiation. For example, there is a kind of Voronoi sterilizer that works better. It is filtered through a filter under the cabinet, and there is a fragrance under the machine, so the sterilized book will have a faint fragrance.