Yes, synthetic EMFs can be harmful. the pathetic part is that the more we know the more harmful is the choice of signals. The book Invisible Rainbow charts a lot of this. I would still disable every phone mast - very easy to do.

I also know a few people who have switched off their 5GHz wifi as it gave them headaches and/or nausea. What you can't see can hurt you. 2.4GHz is also not beneficial, but seems the lesser of two evils.