EHJ December 2003, pages 372-374
The Cassiopea project aims to monitor electromagnetic fields in the environment and provide interested stakeholders with data on levels in their community. Tracey Khanna reports

Despite widespread public concern and a growing international body of research, both of which have been well documented in the pages of EHN this year, the CIEH currently believes that there is "no convincing evidence that environmental exposure to electromagnetic fields (EMFs) generated by the transmission of electricity or mobile telephony is harmful to human health, including that of children." Nonetheless, any concerns about the health effects of EMFs should be recognised as genuine and are an issue for operators and local government alike.

According to Vodafone, which alone has more than 8,000 sites providing a service to 13 million customers, around 50 million people in the UK want to use mobile phones. In addition, businesses are ever more reliant on wire-free networks and the Government would like to see an effective, yet accessible mobile communications system. At the heart of the rapid growth in the popularity of mobile phones is a "vital and comprehensive network" of mobile phone base stations, and there is no doubt that it is these base stations, rather than the handsets themselves, that are the focus of public concerns.

To try and address this, Vodafone is working with local authority partners to pioneer a project which will provide 24-hour electromagnetic field monitoring in selected local authority areas. The device, known as "Cassiopea", is solar-powered and can be housed in a discreet pole or roof-mounted box and records EMF from a range of sources in the 500kHz to 3GHz frequency band, including emissions from TV, radio and any nearby mobile phone base stations. According to the company, "explaining to the public that all mobile phone operators make sure that their base stations comply with precautionary international guidelines* (see box) on EMF exposure levels is one thing, but demonstrating that they do is another."

As part of a trial, the EMF Advisory Unit installed the first such device on the roof of one of its own buildings in Theale, Berkshire. As the project rolls-out, local authorities will be able to choose locations for the siting of the Cassiopea unit. The EMF data is sent automatically to a central server where it is converted into graphical form, setting the ambient levels against guidelines. This can then be transferred to a local authority website for access by interested parties. Stakeholders will be able to access data on EMF levels in a selected part of their community, with the monitor operational 24 hours a day, seven days a week.

Dr Rob Matthews, Vodafone's health physicist and initiator of the project, says: "We want to be as transparent as we can be in our relations with the public but we need to show that the EMF monitoring data is truly independent of us. That is where the local authority comes in. Once we have provided and installed the Cassiopea unit and explained how to verify data, Vodafone does not need to have any more involvement and the local authority can act as an impartial information provider."

Successful 24-hour monitoring has already been carried out by Vodafone's sister companies in Greece and Italy. "We know how well it can work," says Dr Matthews, "but this the first opportunity local authorities in the UK have had to engage in a project of this sort."

EMFs are present everywhere in our environment - they are produced by the local build-up of electric charges in the atmosphere, by the earth's magnetic field and by daylight itself. They are also generated by a range of man-made sources. As well as mobile communications, television and radio, sources include emergency services communications, medical and factory equipment, taxi firms, TV remote controls, electronic car keys, shop security tags and baby listening devices.

The Cassiopea monitoring unit contains three elements:

• a broadband probe;
• a transmitter; and
• a control station.

The transmitter has two GSM modems that allow access to the mobile phone network and provide a link between the monitoring unit and a central control station on which the management software is installed. The broadband probe continuously monitors in the frequency range 500kHz to 3GHz, recording average values over six minute periods. The monitoring unit does not differentiate between sources above 500kHz so it can provide complete reassurance that the total level of EMFs in the atmosphere is within international guidelines.

It is hoped that the Cassiopea local authority project is just the first of many such initiatives across the country.

Further information on the Cassiopea Project is available from Dr Rob Matthews at EMF Advisory Unit, Vodafone House, The Connection, Newbury, Berkshire RG14 2FN, tel: 01635 677706 or e-mail: rob.matthews@vodafone.co.uk