Study rooms are usually considered cleaner comparatively as there is no activity like bathing, or food related activities performed in that area. But there is a possibility of the high microbial load in this area depending on the traffic of people and their hygiene level. Their hygiene level is also including the activity performed prior to coming to reading room. If you have handled something full of microrganisms for example spoiled food or mowed your lawn in the same clothing then possibility of bringing high count in study room is likely. Bacteria are easily stable on paper for up to 72 hours and some are cultivable after seven days.
Not much we can do regarding sanitisation due to delicate nature of books. Usually chemical based sanitisers are harsh on paper. Books with plastic cover can be sanitised with mild concentration of colour safe bleach (e.g. hydrogen peroxide). Usually 3%to 7.5% concentration of hydrogen peroxide can be utilised for sanitisation of papers after performing a test check first. In situation where paper is very delicate, 0.05% of hydrogen peroxide can be utilised. When it is used, contact time of 5 to 10 minute should be utilised.