It depends on how many years the library has been open. There may be formaldehyde in bookcases and some books. But with the passage of time, the concentration of formaldehyde will gradually decrease.

This should be the person in charge of the library or the school. At the beginning of the opening, in addition to formaldehyde's work will be carried out. Don't let people who read books get formaldehyde poisoning. Reading is a good thing.

There are many methods in in addition to formaldehyde, and many indoor in addition to formaldehyde methods can be applied. For example, it is a good choice to set more ventilated windows, put more green plants on the windowsill, put more tourmaline crystals beside the desk next to the bookcase, or put more air purifiers directly in the library.