Electromagnetic Radiation

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This fact can make people uneasy — if light can be used to destroy cells, could our heavy usage of wireless communications perhaps induce this kind of DNA damage and ultimately lead to cancer? This is reasonable to ask, but we have to keep in mind how unbelievably vast the electromagnetic spectrum truly is. Modern communications, from our Wi-Fi networks to phones, are firmly rooted around the microwave end of the scale , with frequencies between MHz and GHz.

In the scheme of the EM spectrum, these photons are of relatively low frequency and low energy. Microwave radiation is undisputedly non-ionizing , and completely incapable of direct DNA damage. In spite of their low energy, microwaves are remarkably effective at heating certain substances through a process known as dielectric heating.

Certain molecules, like water, have regions of partial positive and negative charge which in the presence of an electric field rotate to align themselves in direction of the field. Domestic microwave oven emit photons with a frequency of approximately 2.

Electromagnetic radiation--parameters for risk assessment.

The friction from these rapid collisions is converted to heat, which is precisely why microwaves are so efficient at cooking our predominantly water-based food. This is unfortunately rife for confusion; an entire plethora of blogs and dubious websites assert that microwave cooked food is harmful by dint of being exposed to radiation. Other lines of dubious reasoning rely on misguided extrapolation: if microwave ovens can cook meat, then our Wi-Fi routers and cell phones are therefore cooking us too.

But while thermal effects are certainly possible with microwave radiation, the power output of our communication technology is many orders of magnitude below that of ovens, with typical home routers outputting less than mW.

Electrosensitivity: is technology killing us?

On top of this, ovens are designed to concentrate high power microwave radiation using specially designed waveguides , magnetrons and reflective chambers, a situation neither encountered nor desirable in our conventional communication technology. For example, the field intensity a metre from an EM source will be 4 times greater than the intensity 2 metres away, and 9 times greater than a measurement taken 3 metres away from the source. In practice, this means the strength of an EM source diminishes enormously even over modest distances.

The Electromagnetic Spectrum

Of course, our cell phones by definition come into very close contact with our heads, and so avoiding thermal ill-effect is a major consideration. The heat energy absorbed by tissue exposed to an EM field is given by the specific absorption rate SAR.

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In the European Union, the maximum exposure to EM fields is tightly regulated to a maximum of 2W per kilogram, averaged over the 10g volume receiving the most direct heating to circumvent thermal effects. Importantly, dielectric heating only increases tissue temperature and will not by itself cause any damage to DNA bonds, so SAR should not be taken as a proxy for cancer risk.

Even long-term studies of radar workers show no signs of increased lifetime cancer incidence, despite their exceptionally high levels of exposure to microwave radiation. The dose-response curve did not betray any obvious signs of correlation: in some instances a decrease in risk was even seen, with the possible exception of heaviest users, where biases in the data made it impossible to ascertain any solid relationship.

Similarly, a Danish cohort study did not reveal any obvious link between phone usage and tumour rates. But cancer fears are only one aspect — claims of allergic-like responses to EMR are commonplace, expounded on websites by dubious health gurus.

Such is the extent of belief in EHS that there are numerous dedicated support groups, and inevitable legal action. In Santa Fe, activist groups tried to get public Wi-Fi hotspots banned.

Electromagnetic radiation

In , a French court ruled that a sufferer of EHS should get disability benefit. EHS sufferers in the US have even migrated to areas where Wi-Fi signals are restricted for research and national security reasons. In a particularly tragic case, the parents of 15 year old Jenny Fry claim that EHS was behind her suicide last year, and are campaigning to remove Wi-Fi from UK schools. Yet despite the sincerity of these beliefs and the discomfort experienced by sufferers, the inescapable reality is that there is zero evidence supporting their position.

In provocation trials , sufferers have been completely unable to identify when sources of EMR are present. Subjects also reported negative effects even when exposed to fake EM sources. These results have been replicated in a number of trials, strongly suggesting that the illness sufferers feel is psychological rather than physical, and that for some the belief one is allergic to EM radiation is enough to trigger an unpleasant psychosomatic reaction. Those struggling with EHS appear to be victims not of electromagnetic malaise but rather of a psychological quirk known as the nocebo response.

The more familiar placebo effect is the observation that people given an inactive treatment tend to rate themselves as improving, provided they are unaware the treatment is inert.

What is electromagnetic radiation?

Solar System. Earth System. Global Change. Atmospheric change International protocols Air quality Aerosols and climate. Natural hazards. Space missions. Mission scenarios Instrument design and technology Mission operations Data management. Electromagnetic solar radiation The Sun continuously emits two kinds of radiation: electromagnetic and corpuscular. Electromagnetic solar radiation is a phenomenon by which energy escapes from the Sun at the speed of light in the form of a wave.

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