From J. KERNEY, BE
Sir, - Your correspondent W. T. Coffey has explained very clearly the mechanism by means of which microwaves can produce heating in water and by extension in persons exposed to microwave radiation. Heating, as such, is harmful only if the level is such as to cause inconvenience or burns, whether the source is microwaves, a heater, a fire or any other heating source.
In a microwave oven, the microwaves are enclosed and concentrated in a metal box to achieve the necessary intensity for cooking and reheating purposes.
On a mobile phone mast, however, the aerial is designed to disseminate the microwaves in all directions and the field intensity drops dramatically once one moves away from the immediate vicinity of the aerial elements which themselves are placed reasonably high to radiate effectively.
I am therefore mystified by the conclusion reached in your correspondent's last paragraph since the only hazard posed by microwave masts based on his explanations could be one of heating at ground level. Mobile phone installations have been around sufficiently long for this problem, if real, to have surfaced by now. - Yours, etc.,
Dalkey, Co Dublin.