There is currently a good bit of debate surrounding the effects of low levels of exposure to electromagnetic fields. This page and this page offer two different perspectives. To answer your specific question about cellular radio towers, here are a couple of things to keep in mind:
To learn more, see How Cell-Phone Radiation Works.
- Cellular towers are transmitting at low power in order to limit their range (see How Cell Phones Work to understand why low power makes the cellular concept work). The power level from the tower is not much different from that of a CB radio.
- If you're worried about cellular radio waves, any potential danger would be much more worrisome for the users of the phones, where the transmitter is only inches from the head rather than hundreds of feet away.
Here are some interesting links: