For EM to make a difference you need to be very close as EM waves decrease by an inverse square law. So even a mobile phone would need to be very close regularly while transmitting to be a problem. They do transmit frequently for short bursts all the time. The EM signals from a router will be quite weak and I certainly sit for many hours within 4 ft of mine, There is no comparison with a military radar system which will be very powerful.
Dave