Well Aplha, Beta and Gamma rays gets reduced by somewhat.
^Those are nuclear radiations, and if phone emitted such radiations, it wud not at all be safe to use.
If a person uses his phone for less than 10-12 hrs a day,(here,
use also means that phone is kept near you) Not much harm is cause.
For extra safety, just put phone on airplane mode and instead of wifi, use OTG cable with USB-Ethernet converter. This will eradicate 99.9% of radiation
Still, One can take off from phone 1-day a week. (Although this is not possible, but limit its use to 1Hour that day.)
Edit:- Found this Excellent piece.
*large.stanford.edu/courses/2017/ph241/summerville1/
Clearly, Phone aint that damaging as it is Hyped to be.