The higher up you stay in a population dense city
The higher your RF radiation exposure.
Higher floors provide direct access to signals, making them clearer but also increasing the amount of wireless RF radiation you're being exposed to
Discussion
That is not correct. If you own a device, it changes its power to adapt to the distance from the base antenna. If you stay in a place where signals are shielded, your device will transmit full power. Given the fact that signals decrease with the square of the distance, the device you carry exposes you to almost the 100% of the total power that hits your body.