The rays that fill our days

RADIATION is bewildering. It kills. It cures. In its most extreme form, the risk is clear, even if more

people die from fireworks annually in the US than have died in 45 years of nuclear power operation in that country.

Extreme radiation is cancer-causing with an insidious ability to contaminate the Earth and stalk successive human generations. In its less invasive forms, however, the effects are unclear. Its uses are both awesome and undeniable, but when it comes to health effects, it's a bit like medical opinion views can vary with every turn.

Twentieth-century life has come to the point where radiation is present in practically all activities. Nuclear radiation and radioactive waste cause trepidation, yes - but switching on the radio, television, VDU, microwave oven and mobile phone, through an incessant use of radiation- based technology in the course of a day, does not cost a thought.

There is, however, a growing element of society not so sure about the consequences, and yet not so well informed about the basic physics involved. John O'Dea's Exposure - Living with Radiation in Ireland is commendable in that it provides clear and effective information on both fronts.

Fear has been compounded by increasing manifestations of radiation, mostly man-made, over the past hundred years, "arising from the appurtenances of the technological age". VDUs are as common as the office desk, and mobile phones will soon be as numerous.

A lecturer in environmental physics at Sligo RTC, O'Dea describes his work as "an attempt to take the reader from the realm of hearsay into the first stages of a wider understanding". Unfortunately, the physics comes with a bucketful of acronyms, in radiation-speak, not to mention radiation wave types. This requires some studious consideration. A combination of glossaries, appendixes and graphics helps the reader to get over any information gap.

Radiation extends from ionising radiation, including nuclear power and radon, to non-ionising radiation, including electricity, radio waves, microwaves, lasers, tungsten lamps, the sun, television waves, X-rays and gamma rays - the range of the electromagnetic spectrum.

O'Dea confronts radiation issues and outlines current scientific thinking on possible effects in a clinical, reasoned manner without glossing over risks, doubts, and past sins of science when the hunger for progress blinded pioneers to the full consequences of their discoveries. That evaluation is interspersed with interesting news clippings and photographs.

Its pertinence is underlined by evaluation of radiation issues that have fuelled Irish environmental campaigns of late: Sellafield which, he says, like it or hate it, has a safety record second to none

MMDS television, radon, mobile phone masts, high-voltage power lines. For this alone, it will be consumed by environmentalists eager to bolster their case, and by a public anxious to inform themselves.

Those controversies often coincide with misplaced concern. Take phone masts, which provoked much opposition. Perhaps "far greater concern should be directed at exposure from the handsets (the actual mobile phone) rather than from the cellular towers".

People protest about a transmitter or power line but do nothing to reduce their own exposure to domestic appliances or radon. Concern about radon is justified, he finds, given that more than 7,000 deaths in the US every year are attributable to the effects of this naturally-occurring radioactive gas. As for microwave ovens, he says, older models can leak significant radiation, especially if improperly maintained. Ensuring that the door works properly is a simple but effective precaution.

The emphasis throughout this book is on reasoned caution, with no credence given to hysterical hearsay.