Antinuclear

Australian news, and some related international items

What is electromagnetic radiation? and how safe is it?

Why does this article not mention the difference in vulnerability between children and adults?

What is mobile phone radiation and how safe is it? ABC Science,By science reporter Belinda Smith

“…. What is electromagnetic radiation?

We are surrounded by all sorts of different types of electromagnetic radiation every day: your eyes pick up visible light, your bag is scanned by X-rays at airport security, microwaves heat your lunch and too much ultraviolet light gives you sunburn.

At its essence, electromagnetic radiation is energy comprising an electric field and magnetic field, which travel together, but perpendicularly, in waves.

Sometimes the length of these waves (or wavelength) is very short — a few nanometres for X-rays — while others are much longer — a few centimetres up to kilometres.

It’s these long wavelengths, called radio waves, that are the electromagnetic radiation of choice for mobile phones and base stations.

Unlike shorter wavelengths, such as visible light, radio waves can pass through walls. The longer the wavelength, the better it can penetrate solid stuff.

Another term you might see is frequency, which is the number of times a wave makes a full oscillation each second.

Frequency and wavelength are closely related. Wavelength is the speed of light divided by the frequency, so long wavelengths also have low frequency.

What are ionising and non-ionising radiation?

The radio frequency end of the electromagnetic spectrum is home to what’s known as “non-ionising radiation”, said Rodney Croft, from the University of Wollongong and director of the Australian Centre of Electromagnetic Bioeffects Research.

It’s the high-frequency, short wavelength radiation, such as X-rays, that can tinker with your DNA and are linked to cancer.

These waves are small enough and carry enough energy to knock electrons off atoms, ionising them.

Radio frequency used in mobile communications simply doesn’t have the energy to do that. But that’s not to say it doesn’t exert any effects on the matter it travels through.

“It’s an oscillating wave, which swings between positive and negative,” Professor Croft said

“If you have a bunch of molecules rotating, that causes friction, and energy is given off as heat. It’s how a microwave oven works.”

Does anyone regulate radio frequency limits?

In Australia, mobile phone and base station exposure limits are set by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) and regulated by the Australian Communications and Media Authority.

The ARPANSA standard looks at how much energy a user absorbs from a mobile phone over time.

The maximum limit is currently 2 watts per kilogram of tissue. Phone manufacturers usually specify their maximum absorption rate in their manual.

You can find how much radio frequency is emitted by base stations at the Radio Frequency National Site Archive.

According to ARPANSA, it’s “typically hundreds of times below the [ARPANSA] limits”.

What are the effects of mobile radio frequency on tissues?

So are we microwaving our head whenever we answer the phone? A tiny bit, but not enough to be worried about, Professor Croft said.

He and his team found mobile phone radiation exposure increases the temperature of the outer grey, wrinkled layer of the brain called the cortex, but it’s only “maybe about 0.1 degree, which is very small compared to the temperature variation the body normally has to contend with”, he said.

“We do find that we get a slight change to thermoregulation, so the body, even with that small change, is sending a bit more blood out to the periphery to cool it, so your body doesn’t end up warming up.”

……...What about cancer in rodents?

Mobile phones are classed as “possibly carcinogenic” by the International Agency for Research on Cancer, putting them in the same category as aloe vera, bracken fern and Asian pickled vegetables.

And while radio frequency is non-ionising radiation — remember, it can’t knock electrons off atoms, fiddle with genetic material and trigger tumour growth like ionising radiation can — studies still investigate possible links.

Research published in February this year by the US National Toxicology Program found tumours grew in the nerves around the heart of male rats if they were bathed in extremely high levels of mobile radiation.

But, Professor Croft said, “there were so many difficulties with that study.

………Risks and benefits

Despite research showing no link between safe levels of radio frequency and cancer, telecommunications companies and other organisations do offer suggestions if you want to reduce exposure.

The obvious action, Dr Halgamuge said, is to limit mobile phone use: “You have no control over base stations, because that radiation is around you all the time, but you do have control over your mobile phone.”

The ARPANSA also recommends using hands-free or texting instead of calling, “but none of those things are actually based on any health effects”, Professor Croft said.

………So: does radio frequency have any effect on human tissue, apart from heating it a fraction of a degree?

That question is still open, Professor Wood said.

“Even though some of the evidence [that radio frequency causes damage] on the face of it looks quite compelling, there’s still a question of consistency…….http://www.abc.net.au/news/science/2018-04-30/mobile-phone-radiation-health-explainer-biophysics/9702630

 

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May 4, 2018 - Posted by | AUSTRALIA - NATIONAL, health

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