Bangalore: It's great to have a base station or wireless repeater of your cellular provider, close to where you work or live — your mobile phone works that much better. It's nice that you can receive all the local FM radio transmissions in your town loud and clear. But are you and your family, paying a hidden cost in health for these increasingly familiar facets of urban living? And is anybody trying to understand and mitigate these unseen risks?

Disturbing questions such as these were raised here last week, by researchers at an International conference on Electromagnetic Interference and Compatibility organised by the Society of EMC Engineers with the IEEE EMC Society.

A brief session on biological effects of radio frequency waves raised an amber signal about the lack of standards in India which would prescribe, how much energy and radiation, cellular operators may safely pump out from their network of base stations — that is wireless transmitters — and their multiple repeaters, and how close these can be positioned to habited areas.

Radiation readings

V.S. Tanwar, Director (Technical) of Cogent EMR Solutions, a Delhi-based provider of radiation safety solutions, presented a paper providing a radio frequency radiation pollution perspective of Indian cities. It gave an alarming picture of the levels of such radiation measured in a number of north Indian towns, including Delhi, Gurgaon, Chandigarh, Ambala and Panipat. In crowded work places such as Nehru Place and Bhikaji Cama Place in Delhi, the recordings were between 4000 and 5000 microwatts per square metre. The numbers tended to be even higher, near the offices or towers of leading telecom providers.

Different safety standards

Readings, taken in Bangalore during the conference, revealed radiation levels ranging from 10 and 9800 microwatts per sq. m. While awareness of the dangers from prolonged exposure to such radio frequency radiations is nothing new, the number of different safety standards has caused some confusion, Lt. Col.(retd) Tanwar told The Hindu . Many of them, like the ones generated by the World Health Organisation and the International Commission for Non Ionizing Radiation Protection, take into account only the heating effect on human tissue, which results in very high thresholds. In fact, the standards for ensuring overall health in an environment of electromagnetic radiation, were much more stringent — and by these norms most Indian cities would be considered dangerous, he added.

Safe limit

A number of European nations where cellular phone usage — as well as awareness of its potential hazards — was high, had promulgated the standards published by the Florida-based International Institute for Building Biology and Ecology (IBE), which pegged the safe limit indoors for electromagnetic radiation at 1 microwatt per square metre.

Robert P. Steller, Director of IBE, said the levels shown by the Cogent EMR surveys, should be a cause for concern, because in many cases the most dense networks tended to be in the most crowded work places. In fact, the recommended levels were even lower, for sleeping areas, since the exposure was more sustained for 6-8 hours.

Discussion highlighted the lack of supervision by regulatory authorities when cellular providers put up their base stations: they were often placed on the terraces and rooftops of buildings in the centre of densely populated areas.

Cogent researchers felt a reasonable safety standard that could be enforced in India was 10 microwatts per square metre indoors when people are awake and one-tenth of this during sleep.

Side effects

The medical side effects of such exposure was well documented, said Jitendra Behari, professor at the School of Environmental Sciences of Jawaharlal Nehru University, New Delhi.

Emissions cause problems such as loss of appetite, irritation and fatigue, sleep disturbance — but can also cause more serious nervous disorders especially in children and pregnant women. He felt that prolonged use of mobile phone handsets was also a potential hazard.

Dhiraj Kumar Singh of the Electronics and Radar Development Establishment, Bangalore, quantified the exposure limits for non ionizing radiation for both industrial worker and lay public, at different frequency bands. (Non-ionizing radiation like those from mobile transmissions, TV and Radio towers do not have sufficient energy to change the chemical structure of objects in their path. Hence they need more energy levels to do humans harm when compared with ionizing radiations like X Rays.)

Natural resonance

With the recent jump in FM radio licenses, the possible danger posed by transmitters, which may come up close to human habitats also needed to be factored, other speakers felt. In fact, FM transmissions were 4 or 5 times stronger than mobile base stations and fell in a frequency band (30 MHz to 300 MHz) that was potentially more harmful to humans than cellular telephony which used two bands 900 MHz and 1800 MHz in India. This was because the `natural resonance' of humans fell in the radio band — jargon that means the body could vibrate in tandem with an FM or other radio/ television transmission.

There was urgent need for regulation and both judicial and legislative awareness for the potential hazards of electromagnetic radiation, felt Supreme Court advocates Sushil Tekriwal and Mihir Choudhary.

The Cogent EMR study, "Are we living dangerously," can be downloaded from www.cogentemr.com where the recommended radiation standards of the IBE can also be found.

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