Before I retired, I worked for the California Highway Patrol installing radios and other emergency equipment in their vehicles. We had to move the Radio Whip Antennas on Pickup trucks because of the radiation cause by the 100 watt radios. The didn't want the big whip antenna on the Passenger side as it blocked the view from the passenger side mirror. The antennas were on the pillar behind the driver. We could light a 40 watt Fluorescent tube when we keyed the mic. to transmit and held the tube close by. I don't know if 4 cell phones generate enough radiation to pop, popcorn or cook an egg but it is some thing to think about for those who spend the day with cell glued to their ear.