“If you're looking for ways to limit your exposure to the electromagnetic emissions from your cell phone, know that, according to the FTC, there is no scientific proof that so-called shields significantly reduced exposure from these electromagnetic emissions. In fact, products that block only the earpiece—or another small portion of the phone—are totally ineffective because the entire phone emits electromagnetic waves. What's more, these shields may interfere with the phone's signal, cause it to draw even more power to communicate with the base station, and possibly emit more radiation.”
Over time, the number of cell phone calls per day, the length of each call, and the amount of time people use cell phones have increased. Because of changes in cell phone technology and increases in the number of base stations for transmitting wireless signals, the exposure from cell phone use—power output—has changed, mostly lowered, in many regions of the United States (1).