How long are the airwaves in the human body?

Airwaves? Do you mean radio waves? One of three responses occurs when a human body encounters a radio wave. 1) the wave goes around it, something it can do thanks to its long wavelength; 2) it passes through at the speed of light; 3) it is absorbed as heat. In the normal way of things, the amount of radio energy one encounters than becomes body heat is piddling and is easily dealt with by the body's natural cooling systems. If someone were hugging the top of a broadcast tower, it would be a different story; that person would be partially cooked by the time he dropped off. Constant, dilute exposure is not considered a problem, though the day may come when there is so much radio and appliance traffic that researcher discover adverse effects. Remember that long-wave energy is not ionizing; it's only short-frequency EM (like x-rays) that have the punch to knock electrons off the very atoms of our bodies.