Controversy has arisen again about whether holding a cell phone next to the head for too many minutes a day threatens the brain with electromagnetic radiation. The preponderance of evidence continues to indicate there is no threat. Many people do not realize, however, that we are increasingly surrounded by technologies that emit radiation in the same radiofrequency portion of the electromagnetic spectrum: WiFi routers, Bluetooth transmitters and more.
As the graphic above shows, the radiation emitted in this region is nonionizing: it may heat molecules in the body but does not ionize them (that is, set electrons free). Ionizing radiation, which can tear molecules apart and therefore potentially damage DNA—is the greater worry.
— Mark Fischetti
Graphic courtesy of Jerrold Bushberg. Reproduced with permission from The Essential Physics of Medical Imaging, 3rd edition, by Jerrold Bushberg et al. © Lippincott Williams & Wilkins, 2012.
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13 Comments
Add Commentwhat does ' Ex & Phcm ' stand for?
Reply | Report Abuse | Link to thisThank you,
Trent
Not to dispute the implication of this very informative chart, but the effects of EM radiation are a function of not only frequency but amplitude and proximity. Electronic devices may have dangerously powerful components that are heavily shielded to prevent user exposure, such as microwave ovens. Also, large scale configurations of electronic devices such as those found in large computer centers can produce amplifying complimentary harmonics that could be potentially threatening. I would also not recommend spending a lot of time in front of a satellite transceiver, but I'm no authority.
Reply | Report Abuse | Link to thisEx is a mystery but Phcm is probably photochemical
Reply | Report Abuse | Link to this"Ex is a mystery but Phcm is probably photochemical"
Reply | Report Abuse | Link to thisI have an Ex or two I wish was a solved and forgotten mystery. But I digress...
By the way, the example of 'Fiber telecom' is shown under the infrared spectral range, as IR LEDs are often used for light sources. However, lasers are also frequently used for high performance and long distance fiber optic communications applications - looking into the end of an optical fiber transmitting laser light can immediately produce permanent eye damage. Always assume that light from an optical fiber is dangerous.
Reply | Report Abuse | Link to thisPHCM is more likely to be Pharmaceutical Chemistry.
Reply | Report Abuse | Link to thisNice graph, but the implication that in Mark Fischetti's comment that ionizing radiation can damage DNA is that non-ionizing radiation cannot. This is not correct.
Reply | Report Abuse | Link to thisFor example, blue visible light absorption can induce damage to both nuclear and mitochondrial DNA of cells, which can result in the death of the cell, or in a substantial increase of radical oxygen species generation and increased levels of oxidative stress.
It can also be easily demonstrated that low level magnetic fields can influence cellular metabolic functioning of any cell with active photoreceptor molecules. This follows from the understanding that biologically significant visible-light induced excitations (which are non-ionizing) are dependent on a change in the spin of the electron in the photoreceptor molecule which has been raised to a higher energy level.
While I have no idea whether there is any health risk from the use of cell phones, I don't believe that one can dismiss the possibility of harmful effects of radiation on biological systems, which are capable of detecting and reacting differently to (non-ionizing) photons on the basis of the polarization or incident direction of the photon, simply because the energy level of the radiation is insufficient to induce ionization.
Murray Waldman
I noted the baggage screening,but what about the new passenger screening devices? The airport workers say "Don't worry its not x-ray it's the same thing as your cell phone only a little stronger." I suspect much stronger. Where would these airport screening devices fall on this spectrum?
Reply | Report Abuse | Link to thisA pity that the cosmic ray energies are shown in units of 'Bev'. How very 1950s! These days they are known as Gev.
Reply | Report Abuse | Link to thisThe main point especially for cell phones is in radiated power. If a cell phone that is held to your ear radiates the tissue around it with a 1 watt of power vs 1 milliwatt the result will be entirely different. That is why power levels have dropped with the concerns about it effecting heath even though studies have been inconclusive.
Reply | Report Abuse | Link to thisAll radio sources can effect people or living things it just depends on the proximity of the source and its strength. This will in effect dictate the exposure a person or organism has .
The same hold true from ionizing radiation.
Given the existence of Electroencephalography (EEG), can we really be sure that low levels of non-ionising EM radiation have no effect on the human brain ?
Reply | Report Abuse | Link to this(A typical adult human EEG signal is about 10µV to 100 µV in amplitude when measured from the scalp and is about 10–20 mV when measured from subdural electrodes - from Wikipedia)
The skull is not a diode. If electrical brain activity can be detected outside the scalp then surely (attenuated) radiation from outside can get in ? Since neurons operate on very low electrical potentials perhaps they can indeed be affected by the attenuated radiation from your cell phone.
Woops - Trying to correct the bad characters in my previous post:
Reply | Report Abuse | Link to this(A typical adult human EEG signal is about 10uV to 100 uV in amplitude when measured from the scalp and is about 10-20 mV when measured from subdural electrodes - from Wikipedia)
N′-(phenyl-pyridin-2-yl-methylene)-hydrazine carbodithioic acid methyl ester (PHCM)
Reply | Report Abuse | Link to thisSee for details:
http://mct.aacrjournals.org/content/3/4/403.full
The above was the only non-Vietnamese use of phcm I found.
I found nothing for Ex involving radiation or frequency.