Right poster:
さわがない 保健室では
In the quiet infirmary (Maybe more: Be quite in the infirmary; I think every kanji stuff in green might mean it is related to healthcare. But not sure.)
Left poster:
気をっけよう
熱中症に
ねっちゅうしょうよぼうきょうかけっかん
熱中症予防強化月間
7 月1 日~ 31 日
be careful
heat stroke
network
Heat stroke prevention month
July 1st - 31st
(This is just a part and partly incorrect, but i think you get what it's about)
Middle poster:
インフルエン流
Influenza style (Alot is obfuscated by Yasu so i just looked part of the headline up)
So yeah as stated by
fdsasdf_p this is an infirmary.
And maybe little Yasu got her brain fried during a heat wave. Might explain her behavior.
Or she was there because of an mental ailment she already had to begin with and the heat stroke thing is just a coincidence.
Question would be where the infirmary is located. Elementary school?
Or maybe Orphanage? Anything else?