The book quarantine issue is of interest to me (as well as libraries, as my younger daughter is currently laid off from her job as an assistant librarian - but she expects to go back in August).
We know that dry air increases transmission of CoVid. Books are often stored in dry areas, and books themselves soak up some humidity from the air. So libraries tend to be drier than the outside environment and with very poor ventilation.
We also know in my county that the one big library did in fact become a "hot spot" in early transmission into the homeless community that lives nearby. My daughter's job was more like being a social worker, many times, and people used the library as their living room. Our county has no mask requirement - the library will have one, but how much will that do?
The books themselves bother me only a little. We buy used books all the time. We've been quarantining them in our sunroom (100° plus) for at least 5 days, often more. For very dry, brittle books this would be a disaster, so we're freezing them - DH wants them to be there for like a month. That also kills bedbugs.
However, once out of the freezer, do we then subject them to brief (3 days in the sunroom?) I don't know - I won't be reading those. At any rate, once out of the freezer, they are probably safe to transfer to a bookshelf wash hands, then avoid reading for another week.
(I think all of this is somewhat overkill - because frankly, wearing both a mask and a face shield when going out would be more appropriate - and we haven't started doing that).
