Are you buying a new phone? You should read this
what do you look at a phone when you buy?Compare phones for Great spec and low price,but one thing that we all forget is to compare the SAR ratings (Specific absorption rate). It gives the measure of energy absorbed by the human body when exposed to a radio frequency electromagnetic field. In U.S. it is set at 1.6W/kg over 1 gram of tissue while in the EU it is 2.0W/kg over 10g of tissue.
The galaxy series phone by samsung are known to be the best as they have the lowest SAR ratings (galaxy S4 has SAR value of 0.30W/kg) . The iphones are the mid rangers in this category..90 percent of the time the phone works on low frequency signals but as the signal strength reduces specially in the areas like lifts and where the signal level drops if you are on a call you may be exposing yourself to the high radiation levels. However it is also true that there are no sold evidences of this having a bad effect on our health some reports say it is bad some says it is not. but it is good to be on a safer side.
There is also an android app that alerts you when your mobile is emitting a high frequency signals so that you take appropriate precautions.Give it a try.
Here is a video.
Hope this information proves to be helpful to you.