Influence of electromagentic radiation to human body
At the first presentation of my project and activities from the first month of research (June 2010) I was very impressed by just discovered new wireless communication technology: DASH7. I was amazed by its possibility to penetrate concrete and water, and having in this way a large cover area. But I didn’t thing to another important aspect, which appear as a question at my presentation: how could influence this wireless communication the human body health? Very good question indeed.
A lot of people are afraid of this kind of technology (wireless communications), others didn’t realize that they interfere with us from distance or even very close to us (by example: mobile phones, communication stations, different wireless devices, TV, radio, etc.).
The wireless communication is formed by electromagnetic radiation. A big part of this radiation is natural, it comes from space or even other sources from the Earth (we are protected by this kind of radiation by different layers of materials which covers naturally our planet). Other kind of radiations are generated by different devices created by human (these are the radiation for which we want to determine if they have negative effects to human body health).
Since many years the human race have invented the TV and radio. Both of them use electromagnetic radiation to transmit the signal from the source center to the destination (devices randomly distributed over a large area).
My research doesn’t suppose to create experiments and study the possible negative effects of the electromagnetic radiation to the human body, but to search for research papers and determine the conclusions obtained from different researchers on this area. The most part of the research was based on the influence of the mobile phones (since the mobile phone is a relatively new device which is used today by a very large number of people) to the human body.
Some of the researchers concluded that there is no negative influence to human body, others that there is negative influence to the human body… It was not demonstrated that the electromagnetic radiation could produce negative effects but neither that it couldn’t produce.
From my studies, on other researchers work, I concluded that there is a influence of the electromagnetic radiation (in our case, produced by the wireless communication devices of a Wireless Sensor Network – WSN) but it is not strong enough to produce damage to the tissues of the human body.
First of all: the electromagnetic radiation influence is determined by its frequency. The visible light is also a electromagnetic radiation which have the frequency in a determined range. The frequencies which are lower than the visible light radiation should not affect the human body tissues. The radiations which have a frequency bigger than the visible light radiation frequency is known that they produce negative effects.
In the next figures are presented different types of electromagnetic radiations represented on the frequency range (or wavelength).
The electromagnetic radiations with higher frequency have also more energy.
The frequency of the visible radiation is also called color and it starts from 430 trilion Hz (red color) and reach 750 trilion Hz (violet color). The others colors are in this range of frequencies.
Approximate wavelengths and frequencies for different colors are presented in the next table.
|Color||Wavelenght (nm)||Frequency (THz)|
1 terahertz (THz) = 10^3 GHz = 10^6 MHz = 10^12 Hz
1 nm = 10^-9 um=10^-6 mm=10^-3 m
The white light is a combination of all colors from the visible spectrum.
For the visible radiation (light) it is valid the next formula:
Wavelength = The speed of light in vacuum / frequency
It is important to determine which radiation could affect the structures of atoms of any living being. It is known that the ultraviolet (starting with 7,5*10^14), X rays and Gamma radiation could modify the position of the atoms inside the molecules (being able to cause diseases and even death). This kind of radiation are called ionizing radiation (the photons have enough energy to ionize the atoms). There are not usual devices created by human hand which to produce such high frequencies.
By daily observations, the low frequency radiations, generated by different devices created by human, doesn’t affect the the human body. Only if the power of this radiation is strong enough (stay very close to the source of radiation) it could cause tissues destroying.
It is important that the low frequency radiations penetrate the human bodies and are not absorbed by this one.
All electromagnetic radiations are created by little particles called photons. The energy of a photon increase in the same time as frequency increase (Plank law).
If we take in consideration 3 different types of photons for the electromagnetic radiation, we could compute for each of them the energy produced:
- yellow color radiation, 5*10^14 Hz, energy is about 2eV (electron volt). A bigger power represent a bigger number of photons, but the energy of each photon remains the same.
- mobile phone, 1*10^9 Hz;
- microwave, 2.45*10^12 Hz.
Since the frequency used by the mobile phone and microwave is lower that the frequency of the yellow color, the energy of a photon for them is lower than the energy of a photon from yellow color radiation.
SAR (Specific Absorption Rate) is a unit for measuring the rate of energy absorbed by the human body when it is exposed to a electromagnetic field of radio frequency (the power absorbed by the unit of tissue – W/kg).
The low frequency electromagnetic waves could cause the heating of the tissues. …
On the other side different kind of electromagnetic radiation could be used in medicine for treating different diseases.
At international level the institute which develop activities for protection against non-ionizing electromagnetic radiation is called ICNIRP (International Commission on Non-Ionizing Radiation Protection). In this commission are included independent scientific experts and it is organized in: Main Commission, 4 scientific committee (epidemiology, biology, physics and engineering) and consultant experts on different domains of research.
In our country the Institute of Public Health from Iasi have made many researchs for determining the effects of non-ionizing electromagnetic radiation to the human body. After these researches it was developed a new set of standards which to be used in our country.
The European Commission also started to analyze the effects of non-ionizing electromagnetic radiation to the human body and environment. Their analyze was based on the research papers and experiments developed by different science researchers. At their conclusions they also have create some guidelines for mark the future point of research on this idea.
First of all, they have divided the non-ionizing radiation on different levels:
- radio frequency fields (RF fields);
- intermediate frequency fields (IF fields);
- extremely low frequency fields (ELF fields);
- static fields.
|Domain of frequencies||Frequencies||Source of field|
VDU (video screens)
MRI and other diagnose/scientific equipments
|ELF||0 – 300Hz
Elecrical engines in cars, trains and trams
|IF||300Hz – 100kHz||Some typical examples could be: VDU, anti-thiefs devices from stores, control access, card readers and metal detectors|
|RF||100kHz – 300GHz||Television and tv, mobile phones, microwaves, radar, radio transmitters (mobile or fixed), personal mobile radio.|
“In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation.”
Into the European Commission report there are specified the next conclusions and specifications:
“Radio frequency fields (RF fields)
It is concluded from three independent lines of evidence (epidemiological, animal and in vitro studies) that exposure to RF fields is unlikely to lead to an increase in cancer in humans. However, as the widespread duration of exposure of humans to RF fields from mobile phones is shorter than the induction time of some cancers, further studies are required to identify whether considerably longer-term (well beyond ten years) human exposure to such phones might pose some cancer risk.
Recent studies have not shown effects from RF fields on human or animal reproduction and development. No new data have appeared that indicate any other effects on human health.
Intermediate frequency fields (IF fields)
Occupational exposure to IF fields in certain areas is considerably higher than exposure to the general public. However, very little research on IF and health risks in occupational settings or for the general public have been presented since the previous opinion, and no epidemiological studies have appeared. Consequently, the data are still too limited for an appropriate risk assessment.
Extermly low frequency fields (ELF fields)
The few new epidemiological and animal studies that have addressed ELF exposure and cancer do not change the previous assessment that ELF magnetic fields are a possible carcinogen and might contribute to an increase in childhood leukaemia. At present, in vitro studies did not provide a mechanistic explanation of this epidemiological finding. No new studies support a causal relationship between ELF fields and self-reported symptoms.
New epidemiological studies indicate a possible increase in Alzheimer’s disease arising from exposure to ELF. Further epidemiological and laboratory investigations of this observation are needed.
Recent animal studies provided an indication for effects on the nervous system at flux densities from 0.10-1.0 mT. However, there are still inconsistencies in the data, and no definite conclusions can be drawn concerning human health effects.
Very few recent in vitro studies have investigated effects from ELF fields on diseases other than cancer and those available have very little relevance. There is a need for hypothesis-based in vitro studies to examine specific diseases.
It is notable that in vivo and in vitro studies show effects at exposure levels (from 0.10 mT and above) to ELF fields that are considerably higher than the levels encountered in the epidemiological studies (μT-levels) which showed an association between exposure and diseases such as childhood leukaemia and Alzheimer’s disease. This warrants further investigation.
Although a fair number of studies have been published since the last opinion, the conclusion drawn there stands: there is still a lack of adequate data for a proper risk assessment of static magnetic fields. More research is necessary, especially to clarify the many mixed and sometimes contradictory results.
Short term effects have been observed primarily on sensory functions for acute exposure. However, there is no consistent evidence for sustained adverse health effects from short term exposure up to several teslas.
The scientific rationale has identified a number of areas characterized by insufficient and contradictory information regarding possible health associated effects from the various frequency bands of the EMF spectrum. It is recommended that certain knowledge gaps are filled.”
Other important ideas:
- in case of mobile phones, before they can be introduced into the European market they have to show compliance with the requirements of European directives, i.e. it has to be shown that the limits for the amount of power absorbed in the human body are not exceeded. Standardised methods specified by the European Committee for Electrical Standardisation (CENELEC) are used to test mobile phones in Europe. The limit for mobile phone use is the specific absorption rate (SAR) of 2 W/kg for the human head.
- in our days the digital systems require more transmitters than the older analogue systems.
- the usual frequencies that are allowed for industrial, scientific, and medical applications are similar to most industrial sources: 27 MHz, 433 MHz and 2.45 GHz.
- ***, How Light Works, http://science.howstuffworks.com/light3.htm
- ***, Wikipedia – Light, http://en.wikipedia.org/wiki/Light
- ***, USByte, http://www.usbyte.com/common/approximate_wavelength.htm
- Goiceanu C. & Danulescu R., Activities concerning non-ionizing electromagnetic radiation protection at the Institute of Public Health of Iasi, Journal of Preventive Medicine, 2007, Iasi
- ***, Preliminary opinion on possible effects of electromagnetic fields (EMF) on human health, Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) – European Comission – Public Health and Risk Assessment, 2006
- ***, Health effects to exposure to EMF, Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) – European Comission – Directorate-General for Health & Consumers, 19th January 2009