You know what to do

It's no different than other towers, except that it sits pretty much right on top of the school building. Since RF radiation follows the inverse square law, it means that if you halve the distance to the transmitter, you quadruple your exposure.

In other words, you never want to be close to those towers if you value your health. In this case teachers and children are being irradiated with levels that are probably on par with having a WiFi transmitter right next to you 8 hours a day, every single day you are at that school. The levels might be even higher, we don't know and the article does not say.

This is not like an occasional call with a mobile phone, where you talk for a couple of minutes and then hang up. That is an ongoing non-stop radiation, and since such radiation is cumulative (as far as we know), it is a really bad idea to put towers on school yards.

It doesn't matter what the FCC limits say. The FCC limits are tested for heating for 10 minutes on a dummy head made of jelly. No one ever tested irradiating living humans with such levels, let alone school children, every day of their lives.

As far as power transmission lines, their radiation is in another spectrum which is mostly low-frequency magnetic and electric fields. You definitely do not want to live close to those either. Such fields can be equally damaging, however the mechanisms for damage is different because of the different frequency. It does not make them any safer however. Such transmission lines have been implicated in childhood leukemia for example. Of course the power companies deny these connections as vehemently as the cellular industry deny microwave harm. As long as the amount of $$$ flowing in, is more than the cost of potential litigation from harm, they will keep this party going.