- Electromagnetic Field Emissions (EMF) Monitoring from a mobile phone mast in Nailsworth.
In 2000 there were about 25 million mobile phone users in the UK. That's about one phone per every two people. There are today about 50 million phone users now an even greater range of services are being made available through the third generation of mobile phones.
When you listen to the radio, watch TV or cook dinner in a microwave oven, you are using electromagnetic energy. To give an idea, electromagnetic waves at 102.2 MHz is associated with the radio station Jazz FM and 98.2 MHz with Radio1. All electrical equipment produces an electromagnetic field from the use of electricity provided by the wall socket.
Radiation that members of the public experience throughout their lives can be categorised into two areas; ionising radiation and non-ionising radiation. They are categorised by the quantum energy that is contained in each of the waves and hence their ability to damage biological tissue.
Non-ionising radiation (NIR) is the term given to the part of the electromagnetic spectrum where there is insufficient energy to cause ionisation in living matter. It includes static and power frequency fields, radiofrequencies, microwaves, infra-red, visible and ultraviolet radiation. Microwave ovens, hair dryers, fridges, televisions all emit non-ionising radiation.
On the other hand, when "Ionising" radiation passes through the tissues of the body, they have sufficient energy to damage DNA. Some ionising radiation is better known to the general public under the term X-ray, used for hospital treatments, or gamma rays used to destroy cancerous cells in Radio-therapy. Natural ionising radiation also exist in the form of ultraviolet light, emitted by the sun and filtered in part by the ozone layer.
Mobile telephones are two-way radios. When you talk into a mobile telephone, it picks up your voice and converts the sound to radiofrequency energy (or radio waves). The radio waves travel through the air until they reach a receiver at a nearby base station. The base station then sends your call through the telephone network until it reaches the person you are calling.
When you receive a call on your mobile phone, the message travels through the telephone network until it reaches a base station close to your phone. The base station then sends out radio waves that are detected by a receiver in your telephone, where the signals are changed back into voice or data.
Depending on the equipment and operator, the frequency that each operator utlises is either 900 MHz, 1800 MHz or 2100 MHz.
Base stations are designed for a number of different purposes, such as to provide coverage to a wide area or to increase capacity in a heavily congested area. Base stations are divided into three "cell" categories.
A tremendous effort since the end of the Second World War has been put into research into the possible effects of radiofrequency (RF) on human health.
Literally 1000s of studies have been undertaken and "despite extensive research, to date there is no evidence to conclude that exposure to low level electromagnetic fields is harmful to health (World Health Organisation 2003)".
RF fields penetrate exposed tissues to depths that depend on the frequency - up to a centimetre at the frequencies used by mobile phones. RF energy is absorbed in the body and produces heat, but the body's normal thermoregulatory processes carry this heat away. All established health effects of RF exposure are clearly related to heating. Exposure guidelines have been produced by a number of bodies around the world, including the National Radiological Protection Board (NRPB) and the International Commission for Non-Ionising Radiation Protection (ICNIRP), that ensure that heating within the human body as a result of exposure to RF energy does not result in a hazard to health. The guidelines are precautionary in themselves and are set at levels in excess of 10 (NRPB) and 50 (ICNIRP Public) times below the level at which a core body temperature rise represents a hazard to health. These guidelines are designed to assure the safety of all persons regardless of age and health.
While RF energy can interact with body tissues at levels too low to cause any significant heating, non-heating effects continue to be the subject of current research.
Although there are no specific legal provisions covering non-ionising radiation, the control of exposure to the public is governed by the provisions of the Health and Safety at Work Act 1974 and the Management of Health and Safety at Work Regulations 1999. Under the above legislation, the employers are under the duty to care to ensure that no worker, or member of the public, is placed under any undue hazard.
When assessing compliance with legislation, the Health and Safety Executive (HSE) refers to the guidelines issued by the NRPB. In March 2001, mobile phone operators in the UK voluntarily committed to comply with the international exposure recommendation of the European Union (based upon the precautionary ICNIRP Public exposure guidelines). Each planning application is accompanied by a declaration confirming the design of the proposed radio base complies with the EU public exposure recommendation.
Mobile phone manufacturers for the UK and EU market have voluntarily agreed to produce equipment that meet the ICNIRP recommendation and this can now be seen in almost every new handset instruction manual as the "SAR" value, the Specific Absorption Rate.
How does Stroud District Council control and monitor radiation from mobile phone masts?
In early 2004, Stroud District Council met Vodafone representatives to discuss a project to monitor the radiation from an existing mast installed in Nao;sworth.
The Environmental Health Department, driven by its pro-active approach, agreed to work together with Vodafone and a monitoring unit was installed at a site in Nailsowrth in December 2004.
The project is one of the first in operation in the UK and the objective is to provide a simple and affordable service which gathers data for the local community and other stakeholders in a clear and comprehensible manner. The project allows for instant verification of the EMF level in the environment to enable comparison with current international guidelines.
The monitoring system provides data 24 hours a day, seven days a week and GSM technology to send information to a central server and ultimately to this web page.
The system comprises two elements: a remote monitoring unit and a central control station, or server.
Data is transmitted back to the server from the monitoring unit by two GSM modems.
