Wednesday, July 20, 2011

Is RF Radiation from Cell Phones Dangerous?

A very controversial subject is whether RF radiation from cell phones is dangerous to our health. There are studies showing that it might be and others that show is not dangerous. Many people do not realize that RF radiation at these frequencies is non-ionizing so it cannot damage the cell structure on the molecular level like solar radiation does. However, it can heat the cells (as a microwave oven does to food) but cell phones are relatively low power so does it do any damage to us? Nothing conclusive to date has shown that it is dangerous at the power limits set by the FCC or other international organizations. Below is a recent release about the subject.

The International Journal of Hyperthermia has unveiled a new special issue which addresses the thermal aspects of RF exposure on human health. This special issue resulted from a workshop born out of the controversies surrounding huge growth and use of wireless communication. In the issue, invited experts further refine a quantitative assessment of the effects of thermal energy on tissue damage, fetal development, immune function and neurocognitive behaviour. The special issue papers are available on:

One of the key findings of the workshop and research papers is that while RF exposure standards can surely be refined further, it is fair to say that the present exposure limits set for the general public are far more protective against thermal hazards than recommended limits for the temperature of hot water in the home.

“The purpose of the workshop – and the resulting special issue – was to review current knowledge of the effects of heat on the body that are of potential relevance to setting limits for human exposure to RF,” explains the lead review author, Kenneth R Foster, of the Department of Bioengineering at the University of Pennsylvania. “Thermal damage to the body is clearly a very large topic; our discussion and this special issue focuses on thermal effects that are likely to be relevant to setting RF exposure limits.”

“We examined the most appropriate health endpoints for a given tissue or system, appropriate time periods for acute and chronic exposure, time-temperature thresholds for adverse effects, as well as cost effective and targeted research to help us better understand and define human exposure standards,” continued Foster.

“The upshot was that current RF limits, as recommended by the WHO and adopted by the majority of the world’s governments, are – in thermal terms – far below temperatures that could harm the body,” says Foster. “Indeed, under ordinary environmental conditions, exposure at the whole body limits for the general public, will lead to no detectable increase in core body temperature due to thermoregulatory responses.

That said, both sets of current guidelines on exposure to radiofrequency are subject to limitations, despite the fact that they form the basis for exposure guidelines throughout most of the world. The IEEE (Institute of Electrical and Electronics Engineers) and the ICNIRP (International Commission on Non-Ionizing Radiation Protection) limits set out basic restrictions in terms of power absorbed in tissue. However, the biologically significant quantity is the thermal exposure (increase in temperature and duration of exposure to elevated temperature).

Within the human body, time-temperature functions for thermal damage to different tissue types varies widely and current limit definitions are complex and difficult to explain to the public. In addition, new technologies employing high-power mmWave sources are coming into use and the possibility of human exposure to such energy at potentially injurious levels is increasing.

“If the limiting hazards of RF energy are indeed thermal, several questions must be addressed,” says Mark Dewhirst, Professor of Radiation Oncology, Pathology and Biomedical Engineering at Duke University. “Are current limits adequate to protect diverse tissues from thermal injury? Would it make sense to move to a time-temperature based limit? Are present standards adequately protective for exposures to the types of energy employed by modern electronic devices?”

I am sure there will be more to come on this subject. What do you think?

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