The important harmful elements of the books in libraries and old books.
Various novel swine-origin influenza, bacteria, virus, colon bacillus, dust, fungus or infectious bacteria exists on library books in library.
Chemicals such as ammonia, formaldehyde or xylene which is produced during book fabrication are well known as fatal material causing cancer.
Old books are the habitats for book worms. It shorten book life time and results skin troubles for people.