Which are the different types of electromagnetic radiation? What is ionizing radiation, what is low and what high frequency radiation? What is the difference of artificial from natural radiation? Are there health effects? What scientists disagree on? Why the research results are contradictory?
What is electromagnetic radiation?
Electromagnetic radiation is energy fields produced by electrically charged particles.
There are natural types of radiation (solar and other cosmic radiation the earth's magnetic field, Shumman waves etc.) and artificial radiations (from electrical devices, cables, mobile telephones, antennas, radar etc)
Electromagnetic radiation is divided into categories according to the transmission frequency:
- Non-ionizing Low Frequency Radiation from electrical and electronic devices, cables, household electrical installations, transformers etc.
- Non-ionizing High Freuency Radiation from cell phones and cell phone masts, wireless internet (WI-FI), cordless phones (DECT), bluetooth devices, alarm systems, microwave ovens, wireless game consoles, broadcasting antennas, radars for military, airports and ports, weather radars, satellites, police communications (TETRA) etc.
- Ionizing radiation = Radioactivity (frequency higher than visible light) from x-rays, UV and other cosmic radiation, radon gas that flows from the earth ground, uranium (used in nuclear power plants), radioactive materials located in various rocks etc.
Is only ionizing radiation harmful?
The separation of electromagnetic radiation to ionizing and non-ionizing, creates the false impression that ionization the only biologically harmful process.
Ionizing radiation (= radioactive) activates the production of free radicals in the human body cells and can cause changes in the structure of the chromosomes of the cell membrane (mechanisms associated with cancer development).
Non-ionizing radiation is artificial and very recently introduced on the environment, while ionizing radiations have always existed in the evolution of the human species, which means that we have developed some coping mechanisms.
And as you can read in our article on radioactivity, specific types and dosages of ionizing radiation may even benefit us (radiation hormesis theory).
On the other hand, the constant and increasing exposure to non-ionizing radiation from the power grid, mobile phone masts and dozens of new wireless applications that are added daily, can cause significant health effects through mechanisms other than ionization.
“A major contemporary threat to the health of Society is man-made ‘electrosmog’. This non-ionising electromagnetic pollution of technological origin is particularly insidious, in that it escapes detection by the senses – a circumstance that, in general, tends to promote a rather cavalier attitude, particularly with respect to the necessity of ensuring an adequate degree of personal protection. Yet the nature of the pollution is such that there is literally ‘nowhere to hide’.” Dr. Gerard Hyland, Biophysics, University of Warwick, 2 times Nobel Prize contender Medicine 
What is the point of disagreement between scientists about the effects of non-ionizing radiation?
Scientists disagree on the levels of non-ionizing radiation that cause health effects.
To date safety limits are set taking into account only the thermal effects of high-intensity fields. These values are encountered rarely and only in the immediate vicinity of powerful radiation sources (eg radio antennas).
In recent years, a significant portion of scientists argues that according to recent research data, there are health effects from much lower non-thermal exposure levels.
According to an increasing number of epidemiological and experimental studies, even slight exposure to non-ionizing electromagnetic fields increases the risks of cancer, can be accompanied by nervous disorders and disruption of the circadian rhythms and seems capable of affecting developing organisms. The results of many in vivo and in vitro studies show increasing clearly the interaction mechanisms underlying such disorders and illnesses, centered mainly in cell membrane, lead to disruption of melatonin secretions, ornithine decarboxylase activity and T-lymphocyte efficacy, testifying to the probable role of non-ionizing radiation in promoting cancer." European Parliament Resolution B3-0280/92 
How can low levels of non-ionizing radiation affect our health?
The human body has numerous biological reactions at low (non-thermal) levels of artificial radiation: increaseδ cell proliferation, production of stress proteins, increased activity of free radicals, calcium outflow, increased permeability of blood-brain barrier, miscoordination of hydrogen-oxygen bonds etc. .
The guide of the International Commission for Electromagnetic Safety (IECEM) analyzes the non-thermal effects and mechanisms of interaction with humans.
The potential to cause health effects depends not only on the intensity of electromagnetic fields but also on the duration and frequency of exposure.
Short term and periodic exposure, even at high field intensities, is usually not dangerous because the human body can repair any damage (possible exceptions to people with weakened immune systems, the elderly, pregnant women and children).
On the other hand, the continuous and simultaneous exposure to multiple sources of radiation, creates chronic biological responses that could lead to health effects.
Which effect of artificial radiation may be linked to a plurality of health symptoms?
One of the main causes of health effects according to Dr. Blank, Columbia University professor and researcher in bioelectromagnetism, is the fact that our cells have a stressful reaction to artificial radiation, as they do with other environmental toxins (heavy metals etc.)
The human DNA functions as an antenna which receives even low power low and high frequency signals and commands cells to produce stress proteins.
The mechanism of adaptation to stress triggers our hormonal system to cope with any challenge presented. Unfortunately it is designed to operate for a temporary period.
Chronic stress protein production is:
- associated with sleep problems, depression, headaches, gastric and skin problems, obesity, heart disease, asthma, infections, etc. 
- exhausts the immune system and leads to autoimmune diseases such as rheumatoid arthritis, Crohn's Lyme, lupus, disease Crohn, multiple sclerosis, diabetes, etc. 
The above effect is a possible explanation for the results of a significant number of studies linking artificial radiation with leukemia, cancer of the breast, skin, brain, testes and salivary gland, blood clots, diabetes, miscarriagies, male infertility, Alzheimer, insomnia, neurotic disorders, depression etc.
“The key point about electromagnetic pollution that the public has to realize is that it is not necessary that the intensity be large for a biological interaction to occur. There is now considerable evidence that extremely weak signals can have physiological consequences. These interactive intensities are about 1000 times smaller than the threshold values formerly estimated by otherwise knowledgeable theoreticians, who, in their vainglorious approach to science, rejected all evidence to the contrary as inconsistent with their magnificent calculations. These faulty estimated thresholds are yet to be corrected by both regulators and the media.”Abraham Liboff, researcher, Center of Molecular Biology and Biotechnology, University of Florida Atlantic 
What is the difference between artificial (man made) and natural radiation?
1. The levels of cosmic radiation is minute in relation to artificial radiations while their frequencies are quite different.
"Thus in the frequency range 100 kHz to 300 GHz, 50 years ago it was scarcely possible to measure 10 pW/cm2 on the ground in our countries. Today, depending on the location, values one million to one thousand million times higher are recorded because of the explosion of telecommunications." European Parliament Resolution B3-0280/92 
The earth's magnetic field which is stronger than most artificial electromagnetic fields but this field is static. In contrast to alternating fields, static fields do not continuously change polarity, causing changes in the alignment of the molecules and atoms.
2. Artificial radiations have unnatural waveforms with constant repetitive pattern width, pulse etc.
New York University 
"The problem is, man-made electromagnetic exposures aren’t “normal.” They are artificial artifacts, with unusual intensities, signaling characteristics, pulsing patterns, and wave forms, that don’t exist in nature. And they can misdirect cells in myriad ways. Every aspect of the ecosystem may be affected, including all living species from animals, humans, plants and even microorganisms in water and soil. We are already seeing problems in sentinel species like birds, bats, and bees. Wildlife is known to abandon areas when cell towers are placed. Radiofrequency radiation (RF)—the part of the electromagnetic spectrum used in all-things-wireless today—is a known immune system suppressor, among other things. RF is a form of energetic air pollution and we need to understand it as such.” Blake Levit, author of "Electromagnetic Fields, A Consumer's Guide to the Issues and How to Protect Ourselves" 
3. Artificial radiations are have been very recently added to the human environment and we have not developed evolutionary mechanisms to address them.
"Furthermore, given the relatively short time for which we have been exposed to it, we have no evolutionary immunity either against any adverse effects it might directly have on our alive organism or, indirectly, against its possible interference with certain electromagnetic processes of natural origin, which appear to be essential for homeostasis, such as, for example, the Schumann resonance – a weak electromagnetic field that oscillates resonantly in the cavity between the earth’s surface and the ionosphere at frequencies close to those of human brain rhythms, isolation from which has been found to be deleterious to human health. What distinguishes technologically produced electromagnetic fields from (the majority of) those of natural origin is their much higher degree of coherence. This means that their frequencies are particularly well-defined, a feature that facilitates the discernment of such fields by living organisms, including ourselves. This greatly increases their biological potency, and ‘opens the door’ to the possibility of frequency-specific, non-thermal influences of various kinds, against which existing Safety Guidelines – such as those issued by the International Commission for Non-ionising Radiation Protection ( ICNIRP) - afford no protection". Dr. Gerard Hyland, Biophysics, University of Warwick, 2 times Nobel Prize contender Medicine 
The radiation from electrical appliances, power cables etc exist many years and we are fine. Why should we reduce our exposure to them?
1. Our exposure to radiation due to electricity has increased significantly due to:
- greater use of electric and electronic devices
- greater power consumption
- turn to electrical solutions for cooling and heating (eg instead of oil, natural gas)
- use of plastic cables in homes instead of grounded steel cables
2. The radiation emitted by cables and devices today has a more aggravating waveform
The extensive use of electronic non-linear load devices such as fluorescent lamps, AC adapters, dimmer electronic switches, inverter air conditioners, plasma TVs, photovoltaic systems etc. result in deformation of the plain sinusoidal signal of 50-60Hz mains with high frequency harmonics.
This phenomenon is called "Dirty Electricity" because it causes overheating of the neutral conductor and premature aging of equipment. Some scientists believe that the new waveform is particularly burdensome for humans  .
3. Electricity does have health implications
Previously it was thought that low frequency radiation does not have enough energy (photons) and therefore our body could not distinguish it from the natural electromagnetic waves produced by the body (thermal noise).
But research since 1977 (Adey and Bawin) has shown that organisms can react to exogenous electromagnetic signals of very low intensity and experience an even greater reaction to them than from stronger signals.
The explanation of the phenomenon of amplification of an exogenous signal gave Gilbert and Rodbell the Nobel Prize in 1994. The G proteins integrate multiple signals outside the cell and activate various cell amplification systems. Because of these, a single photon of electromagnetic energy is sufficient to start the massive calcium entry into the cells, activating several biological functions. 
To date studies have linked low-frequency radiation with miscarriages, Alzheimer's, leukemia, breast cancer, skin cancer, insomnia, thrombosis, damage to DNA, diabetes, multiple sclerosis, neurotic disorders, depression etc.
The alternating magnetic fields have ben rated as "possible carcinogens" by the National Environmental Health Institute, USA (NIEHS)  and by the International Agency for Research on Cancer (IARC) of the World Health Organisation  .
“Very recently, new research is suggesting that nearly all the human plagues which emerged in the twentieth century, like common acute lymphoblastic leukemia in children, female breast cancer, malignant melanoma and asthma, can be tied to some facet of our use of electricity. There is an urgent need for governments and individuals to take steps to minimize community and personal EMF exposures.” Samuel Milham MD, MPH, Medical epidemiologist in occupational epidemiology. 
Radiation from radio antennas exists for many years and we are fine. Why are the lower power cell phone masts, Wi-Fi etc dangerous?
1. Today we receive a much larger amount of radiation from cell phone masts
Broadcasting antennas are usually situated on hills in non-urban areas and therefore, although emit with more power, their signal reaches us faint.
Research in 2000 in Sweden showed that emissions from radio and tv broadcasting antennas were only 13% of wireless radiation in the suburbs and 1% in city centers  .
The largest proportion of our greatly increased exposure to wireless radiation comes from cell phone masts, mobile phones, cordless phones and wi-fi modems.
2. The radiation emitted by cell phone masts, Wi-Fi etc have a more aggravating waveform
The electromagnetic waves from cell phone masts, cordless phones, wireless modems, etc. have a digital modulation (see photo below), while those of the older broadcasting antennas had analog modulation (see above photo).
The digital square waveform comprising of high intensity pulses is considered biologically more powerful than the older analog sinusoidal waveform.
The conclusion of the Panel BioInitiative Working Group , which took into account more than 2000 surveys on the subject of electromagnetic radiation was that:
"There is substantial scientific evidence that some modulated fields (pulsed or repeated signals) are bioactive, which increases the likelihood that they could have health impacts with chronic exposure even at very low exposure levels. Modulation signals may interfere with normal, non-linear biological processes. Modulation is a fundamental factor that should be taken into account in new public safety standards; at present it is not even a contributing factor. To properly evaluate the biological and health impacts of exposure to modulated RF (carrier waves), it is also essential to study the impact of the modulating signal (lower frequency fields or ELF-modulated RF). Current standards have ignored modulation as a factor in human health impacts, and thus are inadequate in the protection of the public in terms of chronic exposure to some forms of ELF-modulated RF signals. The current IEEE and ICNIRP standards are not sufficiently protective of public health with respect to chronic exposure to modulated fields (particularly new technologies that are pulse-modulated and heavily used in cellular telephony)."
3.TV and radio broadcasting antennas can also cause damage
Research has linked proximity to them with childhood leukemia, brain cancer and melanoma (Merzenich  , Ha  , Hallberg  , Hocking .
"Scientific studies at the cellular level, whole animal level and involving human populations, shows compelling and comprehensive evidence that RF/MW exposure down to very low residential exposure levels, levels which are a minute fraction of present “safety standards”, results in altered brain function, sleep disruption, depression, chronic fatigue, headache, impaired memory and learning, adverse reproductive outcomes including miscarriage, still birth, cot death, prematurely and birth deformities. Many other adverse health effects have been found, predominantly cancer of many organs, especially brain cancer, leukaemia, breast cancer and testicular cancer. Studies have also found that RF/MW exposed parents have more children with CNS cancers and other health defects. (...) Hence there is strong evidence that ELF and RF/MW is associated with accelerated aging (enhanced cell death and cancer) and moods, depression, suicide, anger, rage and violence, primarily through genotoxic damage, alteration of cellular calcium ions and the melatonin/serotonin balance." Dr. Neil Cherry, Lincoln University in New Zealand 
Why are research results contradictory?
- research does not take into account the simultaneous exposure of the population to multiple radiation sources
- there is no population not exposed to radiation, in order to make correct comparisons
- some studies exclude sensitive population groups (eg children from the Interphone study)
- some studies do not last long enough to show differences in the development of diseases such as cancer (required time > 10 years)
- the separation of those exposed to a radiation source is not realistic (eg in the Interphone study, mobile phone users were considered to be also those who spoke only once a week in the mobile... Could they be in the same group of people that spoke three hours every day?)
- the exposure assessment is often simplified based on the distance from the sources which frequently does not correspond to the actual exposure (eg near mobile phone masts we record totally different radiation values in residencies facing the mast compared to those that don't, even if the distance is the same).
- research results are significantly influenced by the source of funding (according to the study by Professor Henry Lai in total 221 studies on the effects of radiation from mobile phones, adverse effects were recorded in 70% of independent research and only 32% on the studies funded be the mobile phone industry  )
When I run up against a brick wall all of ten times and develop a blue bruise each single time, this would be an accurately observed and easily reproducible fact. If I am concerned about it, trying to tell my story or even publish it because I wish to stop this type of wall running, such action will be regarded as premature and unscientific, even as downright fear mongering. And that because there were simply not enough others before or after me who would have done the same thing, thus replication did not take place. Or if it did, the bruising in other people, age groups, skin colors, and with different momenta did not turn quite as blue but rather a shade of green. Anyhow, something is still missing, that is the conclusive explanation of the effect: Why does the bruise develop? And why in this way and no other, why this color, pain, dizziness? What is going on here? Without clear answers to these questions (and a lot more), it will remain scientifically untenable - by a long shot - despite the bruise, despite the pain and dizziness. Wolfgang Maes, German Institute for Building Biology 
If indeed there was a risk, wouldn't our government alert us?
Although the European Union has adopted the 'precautionary principle', which means taking preventive measures before there is certainty about the harmfulness of a substance or product, in the case of artificial electromagnetic fields this declaration has remained on paper.
Given the changes that will be required, the loss of revenue (taxes on mobile phones have become a huge source of revenue for governments) and the interests that will be affected, the authorities wait until there is undeniable health effect in order to react.
To be considered a health effect "proven", it is necessary to reproduce the same each time the same result of study by different universities, institutes and laboratories.
It is not enough when 50 out of the 100 studies show health effects, we need to have all them show the same effects.
The difficulty of reproducing the same results in studies combined with economic pressures delays the goverments taking action.
In the past, however, similar delays have adversely affected the health of the population, as shown by the report of the European Environment Agency about the delayed reactions of the authorities on issues such as asbestos, PCB, X-rays, etc.
"There are reports of biological effects of EMF at levels below the well recognized standards and guidelines. WHO would now like to develop a framework and guidelines that would allow the application of the PP not only for EMF but also for WHO policy generally. It is not question of whether we apply it. It is a question of how we apply it." World Health Organization 
Insurance companies, however, do not wait for the legislation to change. Anticipating future massive compensation claims by citizens (as it had happened in the past and the case of asbestos) they already exclude coverage for the risks associated with electromagnetic fields from the insurance liability.
G.J. Hyland, University of Warwick, International Institute of Biophysics, The Physiological and Environmental Effects of Non-ionising Electromagnetic Radiation’ http://www.feb.se/EMFguru/EMF/Physiological.html
 Actual Or Potential Effects of ELF and RF / MW Radiation on Enhancing Violence and Homicide, and accelerating Aging of Human, Animal Or Plant Cells. Dr Neil Cherry Associate Professor of Environmental Health Lincoln University New Zealand, neilcherry.com/documents/90_s8_EMR_and_Aging_and_violence.pdf
 Mayo Clinic, How Stress Affects Health, http://www.mayoclinic.com/health/stress/SR00001
 Stress Proteins in Medicine, http://www.researchandmarkets.com/reportinfo.asp?report_id=1310105&t=t&cat_id=
 Havas M, (2006) Electromagnetic hypersensitivity: Biological Effects of Dirty Electricity with emphasis on diabetes and Multiple Sclerosis.
 James Oschman, Energy Medicine in Therapeutics and Human Performance
 Camilla Rees- Magda Havas, Public Health SOS - The Shadow Side of The Wireless Revolution
 Hamnerius, Y. & Uddmar, T. (2000). Microwave exposure from mobile phones and base stations in Sweden
 Merzenich, Childhood Leukemia in Relation to Radio Frequency Electromagnetic Fields in The Vicinity of TV and Radio Broadcast Transmitters, Am J Epidemiol. 2008 Oct 3.
 Ha, Radio-frequency Radiation Exposure from AM Radio transmitters and CHILDHOOD leukemia and Brain Cancer, Am J Epidemiol. 2007 Aug 1; 166 (3): 270-9
 Hallberg, Johansson, (2005) FM Broadcasting Exposure Time and malignant melanoma incidence, Electromagnetic Biology and Medicine twenty-four? 1-8
 Hocking, Cancer incidence and Mortality and Proximity to TV Towers, Med J Aust. 1996 Dec 2-16; 165 (11-12): 601-5
 Dr. Martin Blank - Electromagnetic Fields and Cancer - www.youtube.com
 Wolfgang Maes, Science - Really?, Conference 2006 «Building Biology - Architecture - Environmental Medicine»
 World Health Organization Conference on "Application of the Precautionary Principle in Electromagnetic Fields", February 2003