What are the risks of telecommunication masts?

Answer 1

In general microwave frequencies are electromagnetic waves with frequencies in the range of 300 MHz to 300 GHz. In this range is the 2.4GHz is used in microwave ovens to heat food where water, sugar and fats absorb this radiation. This method is called dielectric heating. This is what is harmful to humans and what cooks the food in a microwave oven.

I have heard many rumors of concerned parents claiming cell phone towers at schools are harmful to their children.

A cellular beacon or tower, known as a cell-site, actually controls and limits it's RF output power for the sake of interference in reusable RF channels. This means they specially limit the output power so that the output does not range to far and interfere with other "cells". The best way to bring insight to this phenomena which is very hard to quantify for non-technical individuals who seems to makeup the largest part of the concerned community, is to use relative measures which can be better understood.

In this article we will use mW per square meter as a measure of microwave (harmful) radiation.

The ground-level power densities near typical cellular towers are on the order of 10 mW per sq meter or less while the sun radiates about 250 000 mW per sq meter average per 24 hour day which means, that during the day it's even much more. The radiation from the sun on the earth is about 25 000 times more than the radiation under a cell-site(cell phone tower) per sq meter.

The microwave oven in the kitchen have a magnetron (source of microwave radiation) that can produce in the order of 800W or 800 000mW microwave power, the shielding in the microwave oven will ensure a leakage at 5cm distance of radiation less than 10 000mW per sq meter.

So lets compare electromagnetic radiation magnitudes.

1) Sun average radiation on the earth = 250 000mW per sq meter (full electromagnetic spectrum)

2) Microwave oven leakage (5cm distance) = 10 000mW per sq meter (microwave)

3) Directly under cell site = 10mW per sq meter (microwave)

The safe standard for Specific absorption rate (SAR)is about 2000 mW/kg body tissue for cell phones. Although generally for other devices up to 10 000mW/kg can still be seen as safe.

The amount of radiation may vary according to position and distance, cell-sites are not isotropic radiators, this means that they are directional. The power they produce in front of them in the direction they are focused is much more than the power behind or below them. The antennas are often mounted three on tower to form hexagon cell and to produce a near omni-directional coverage. They appear to be harmless.

Answer 2

Telecommunication masts can disrupt the migration patterns of birds and butterflies, such as the monarch. There is also some concern over the effects of exposure to the electrical field.