https://en.wikipedia.org/wiki/Specific_absorption_rate
Specific Absorption Rate (SAR) is a measure of the rate at which energy is absorbed by the human body when exposed to a radio frequency (RF) electromagnetic field. It can also refer to absorption of other forms of energy by tissue, including ultrasound.[1] It is defined as the power absorbed per mass of tissue and has units of watts per kilogram (W/kg).[2][3]
SAR is usually averaged either over the whole body, or over a small sample volume (typically 1 g or 10 g of tissue). The value cited is then the maximum level measured in the body part studied over the stated volume or mass.
SAR limits set by law do not consider that the human body is particularly sensitive to the power peaks or frequencies responsible for the microwave hearing effect. Frey reports that the microwave hearing effect occurs with average power density exposures of 400 μW/cm2, well below SAR limits (as set by government regulations).
Notes:
In comparison to the short term, relatively intensive exposures described above, for long term environmental exposure of the general public there is a limit of 0.08 W/kg averaged over the whole body. A whole-body average SAR of 0.4 W/kg has been chosen as the restriction that provides adequate protection for occupational exposure. An additional safety factor of 5 is introduced for exposure of the public, giving an average whole-body SAR limit of 0.08 W/kg.
( From https://doi.org/10.1152%2Fjappl.1962.17.4.689 Frey, Allan H (1962). "Human auditory system response to modulated electromagnetic energy". Journal of Applied Physiology.
"Stringent Mobile Radiation Standards Come into Force from tomorrow New Mobile Handsets to comply with SAR Value of 1.6W/KG - Penalty, Random Checks Introduced for Enforcement". Press Information Bureau, Government of India. 2012-
http://www.pib.nic.in/newsite/erelease.aspx?relid=87152
"ICNIRP Guidelines For Limiting Exposure To The Time-Varying Electric, Magnetic And Electromagnetic Fields (Up To 300 GHz)" (PDF). International Commission on Non-Ionizing Radiation Protection. 1998.
https://web.archive.org/web/20140606044606/http://www.icnirp.org/documents/emfgdl.pdf
(March–April 2008). "Mobile Phones: Bad for your Health?". IEEE Potentials. https://doi.org/10.1109%2FMPOT.2008.919701
1998]. "Focusing of therapeutic ultrasound through a human skull: a numerical study"
Journal of the Acoustical Society of America is a monthly peer-reviewed scientific journal covering all aspects of acoustics
"Specific Absorption Rate (SAR) For Cell Phones: What It Means For You". Federal Communications Commission. 2011-
http://www.fcc.gov/guides/specific-absorption-rate-sar-cell-phones-what-it-means-you
The FCC regulations for SAR are contained in 47 C.F.R. 1.1307(b), 1.1310, 2.1091, 2.1093 and also discussed in OET Bulletin No. 56, "Questions and Answers About the Biological Effects and Potential Hazards of Radiofrequency Electromagnetic Fields."
https://transition.fcc.gov/oet/rfsafety/background.html
https://en.wikipedia.org/wiki/Mobile_phone_radiation_and_health
"The effect of radiation from mobile phones and other wireless electronic devices on human health is a subject of interest and study worldwide, as a result of the enormous increase in mobile phone usage throughout the world. As of 2015, there were 7.4 billion phone subscriptions worldwide, though the actual number of users is lower as many users own more than one mobile phone.[ Mobile phones use electromagnetic radiation in the microwave range (450–3800 MHz and 24–80 GHz in 5G mobile). Other digital wireless systems, such as data communication networks, produce similar radiation.
In response to public concern, the World Health Organization established the International EMF Project in 1996 to assess the scientific evidence of possible health effects of EMF in the frequency range from 0 to 300 GHz. They have stated that although extensive research has been conducted into possible health effects of exposure to many parts of the frequency spectrum, all reviews conducted so far have indicated that, as long as exposures are below the limits recommended in the ICNIRP (1998) EMF guidelines, which cover the full frequency range from 0–300 GHz, such exposures do not produce any known adverse health effect. "
// Filmi lõpp "Thank You for smoking "
" The WHO states that "A large number of studies have been performed over the last two decades to assess whether mobile phones pose a potential health risk. To date, no adverse health effects have been established as being caused by mobile phone use." Stronger or more frequent exposures to EMF can be unhealthy, and in fact serve as the basis for electromagnetic weaponry. "
// BASIS for weaponry..
" International guidelines on exposure levels to microwave frequency EMFs such as ICNIRP limit the power levels of wireless devices and it is uncommon for wireless devices to exceed the guidelines. These guidelines only take into account thermal effects, as nonthermal effects have not been conclusively demonstrated.[ ] The official stance of the British Health Protection Agency (HPA) is that “[T]here is no consistent evidence to date that WiFi and WLANs adversely affect the health of the general population”, "
" In 2011, International Agency for Research on Cancer (IARC), an agency of the World Health Organization, classified wireless radiation as Group 2B – possibly carcinogenic. That means that there "could be some risk" of carcinogenicity, so additional research into the long-term, heavy use of wireless devices needs to be conducted "
" Users of wireless devices are typically exposed for much longer periods than for mobile phones and the strength of wireless devices is not significantly less. Whereas a Universal Mobile Telecommunications System (UMTS) mobile phone can range from 21 dBm (125 mW) for Power Class 4 to 33 dBm (2W) for Power class 1, a wireless router can range from a typical 15 dBm (30 mW) strength to 27 dBm (500 mW) on the high end. "
// However:
However, wireless routers are typically located significantly farther away from users' heads than a mobile phone the user is handling, resulting in far less exposure overall. The Health Protection Agency (HPA) says that if a person spends one year in a location with a Wi-Fi hotspot, they will receive the same dose of radio waves as if they had made a 20-minute call on a mobile phone
// !!!
"The HPA also says that due to the mobile phone's adaptive power ability, a DECT cordless phone's radiation could actually exceed the radiation of a mobile phone. The HPA explains that while the DECT cordless phone's radiation has an average output power of 10 mW, it is actually in the form of 100 bursts per second of 250 mW, a strength comparable to some mobile phones "
" Wireless access points are also often close to people, but the drop off in power over distance is fast, following the inverse-square law.[12] However, wireless laptops are typically used close to people. WiFi had been anecdotally linked to electromagnetic hypersensitivity[13] but research into electromagnetic hypersensitivity has found no systematic evidence supporting claims made by sufferers.[14][15]
The HPA's position is that "... radio frequency (RF) exposures from WiFi are likely to be lower than those from mobile phones." It also saw "... no reason why schools and others should not use WiFi equipment."[16] In October 2007, the HPA launched a new "systematic" study into the effects of WiFi networks on behalf of the UK government, in order to calm fears that had appeared in the media in a recent period up to that time".[17] Michael Clark of the HPA says published research on mobile phones and masts does not add up to an indictment of WiFi "
" A decline in male sperm quality has been observed over several decades. Studies on the impact of mobile radiation on male fertility are conflicting, and the effects of the radiofrequency electromagnetic radiation (RF-EMR) emitted by these devices on the reproductive systems are currently under active debate A 2012 review concluded that "together, the results of these studies have shown that RF-EMR decreases sperm count and motility and increases oxidative stress" "
"According to the National Cancer Institute, two small studies exploring whether and how cell phone radiation affects brain glucose metabolism showed inconsistent results."
"Some users of mobile phones and similar devices have reported feeling various non-specific symptoms during and after use. Studies have failed to link any of these symptoms to electromagnetic exposure. In addition, EHS is not a recognised medical diagnosis."
"A 2012 study of low-frequency radiation on humans found "no evidence for acute effects of short-term mobile phone radiation on cerebral blood flow".[21][22] However, several animal studies have demonstrated damage to the blood-brain barrier from phone radiation."
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http://www.emfwise.com/SAR.php
Addressing only Thermal Effects
The other flaw in the SAR standard is its focus on thermal effects only. For more information on non-thermal effects, read the Science Overview. With respect to call duration, Robert C. Kane notes that most of the temperature rise due to the energy absorption occurs in the first 60-90 seconds of exposure. Hence, if energy absorption were the major concern, then a short call would have to be defined as being less than a minute (Kane, 12).
Lack of Strict Guidelines on How SAR is measured
According to Devra Davis, a phone's SAR rating can be off by a factor of 2 to 4, due to differences in measurement by manufacturers, which may test the radiation at different distances from the body/head. Hence, the SAR rating is not the most reliable way to measure a phone. In fact, Devra Davis points out that some of the newer smart phones come with warnings to keep the phone a distance from the body.
Where did we get our SAR standard?
For mobile phones, the SAR standard is 1.6 W/kg for the general public, for the partial body limit. This standard is based on behavioral disturbances observed in monkeys at 4 W/kg.
The Environmental Protection Agency (EPA), however, has noted data showing evidence for biological effects at a SAR of 1W/kg, indicating that our current standard is not protective enough. Other independent scientists have found evidence of harmful effects at even lower SAR's. For example, harmful effects are seen in rat brains after only 2 hours at 0.2 W/kg. To give you an idea of how high 1.6 W/kg is, note that the SAR can already reach 0.001 W/kg at 150-200 meters from a mobile phone mast (cell tower), and health effects have been observed up to 300-400 meters or more from a cell tower. See Table of Effects by Power.
Choosing a Phone by SAR ratings?
Choosing a phone by SAR is most likely to give people a false sense of security that their phone is safer. The RNCNIRP 2011 states that "The Specific Absorption Rate (SAR) used for declaration of a mobile phone safety, equal to 2 W/kg averaged over ten grams of brain tissue, in the opinion of the RNCNIRP, cannot be viewed as sufficiently scientifically grounded in this case, and its use does not guarantee protection of childhood and juvenile health."
The following considerations could turn out to be more important factors than the SAR rating:
UMTS vs. GSM vs. CDMA
Franz Adlkofer says his lab found 10 times the rate of broken DNA with new 3G phones (UMTS system) compared to GSM, as reported in the International Archives of Occupational and Environmental Health, 2008. Other studies suggest that GSM may be more dangerous than CDMA in the tested phone models. However, these studies are not completely independent, and further independent research would be needed to confirm and clarify these findings. Newer technologies are also being developed such as 4G, so these previous studies may quickly become outdated.
Continuous pulse waves
The Council of Europe raised concerns on "continuous pulse waves" which may be more dangerous than non-pulsed waves.
Smart Phones vs. Old-fashioned Phones: Duration of Signals
Perhaps another more important consideration is how frequently a phone is sending signals when one is not actively on a call. Many smart phones (e.g., iPhone, Blackbery, Android), depending upon one's service subscriptions and configured options, may be constantly "connected", continually "polling" the network for new e-mails or instant messages. Hence, just leaving a smart phone with internet/data mode enabled can constitute heavy usage.
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https://cellphones.procon.org/highest-and-lowest-radiation-cell-phones/
https://images.procon.org/wp-content/uploads/sites/11/FCC_Aug1996_Rules.pdf
On Aug. 7, 1996, the FCC created guidelines on cell phone radiation (RF) exposure with input from the Food and Drug Administration (FDA), the Environmental Protection Agency (EPA), the National Institute for Occupational Safety and Health (NIOSH), and the Occupational Safety and Health Administration (OSHA).
The guidelines created a measure of the rate that body tissue absorbs radiation during cell phone use called the specific absorption rate (SAR). The SAR for cell phone radiation was set at a maximum of 1.6 watts of energy absorbed per kilogram of body weight. The limit was set due to the thermal effects of cell phone radiation (all RF radiation can heat human body tissue at high enough levels) – it was not set to mitigate other biological effects cell phone radiation might have such as DNA damage or cancer.
The FCC SAR limit is based upon a cell phone call that averages 30 minutes when the cell phone is held at the ear
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Peaaegu nagu ühestsuust:
Nokia SAR:
https://www.nokia.com/phones/en_int/sar
Your mobile device is a radio transmitter and receiver.
It is designed not to exceed the limits for exposure to radio waves (radio frequency electromagnetic fields), recommended by international guidelines
from the independent scientific organization ICNIRP. These guidelines incorporate substantial safety margins assure the protection of all persons regardless of age and health. The exposure guidelines are based on the Specific Absorption Rate (SAR), which is an expression of the amount of radio frequency (RF) power deposited in the head or body when the device is transmitting.
Samsung SAR:
"Here you can check the SAR Value and related information for your Samsung mobile phone."
https://www.samsung.com/sar/sarMain?site_cd=pk&prd_mdl_name=SM-A530F/DS
"Your mobile device is a radio transmitter and receiver.
It is designed not to exceed the limits for exposure to radio waves (radio frequency electromagnetic fields) recommended by international guidelines.
The guidelines were developed by an independent scientific organization (ICNIRP) and include a substantial safety margin designed to assure the safety of all persons, regardless of age and health. "
#The guidelines were developed by an independent scientific organization (ICNIRP) and include a substantial safety margin designed to assure the safety of all persons, regardless of age and health.
The radio wave exposure guidelines use a unit of measurement known as the Specific Absorption Rate, or SAR. The SAR limit for mobile devices is 2 W/kg.
Tests for SAR are conducted using standard operating positions with the device transmitting at its highest certified power level in all tested frequency bands. The highest SAR values under the ICNIRP guidelines for this device model are:
Head SAR : 0.241 W/Kg
Body SAR : 1.250 W/Kg
During use, the actual SAR values for this device are usually well below the values stated above. This is because, for purposes of system efficiency and to minimize interference on the network, the operating power of your mobile device is automatically decreased when full power is not needed for the call. The lower the power output of the device, the lower its SAR value. "
https://www.rfsafe.com/sar-rating-comparison/apple-iphone-7-sar-level-vs-apple-iphone-7-plus-sar-level/
"The SAR for the GSM iPhone 7 is 1.19 watts per kilogram (w/kg) at your head, and 1.09 w/kg when worn on the body. The iPhone 7 GSM hotspot/Airplay SAR is 1.14 w/kg. The SAR for simultaneous transmission (cellular plus Wi-Fi) is 1.56 w/kg next to your head, 1.51 w/kg when worn on the body, and 1.58 w/kg when used as a hotspot .
The SAR for the CDMA iPhone 7 Plus is 1.09 watts per kilogram (w/kg) at your head, and 1.10 w/kg when worn on the body. The iPhone 7 Plus CDMA hotspot/Airplay SAR is 1.13 w/kg. The SAR for simultaneous transmission (cellular plus Wi-Fi) iPhone 7 Plus is 1.45 w/kg at your head, 1.51 w/kg when worn on the body, and 1.58 w/kg when used as a hotspot ."
International Commission on Non-Ionizing Radiation Protection
https://en.wikipedia.org/wiki/International_Commission_on_Non-Ionizing_Radiation_Protection
https://www.icnirp.org/
"ICNIRP is an independent non profit scientific organization chartered in Germany. It was founded in 1992 by the International Radiation Protection Association (IRPA) to which it maintains close relations."
"The International Radiation Protection Association (IRPA) is an independent non-profit association of national and regional radiation protection societies, and its mission is to advance radiation protection throughout the world. It is the international professional association for radiation protection. "
"IRPA was formed on June 19, 1965, at a meeting in Los Angeles; stimulated by the desire of radiation protection professionals to have a world-wide body. Membership includes 50 Associate Societies covering 65 countries, totalling approximately 18,000 individual members"
President
Roger Coates
Key people
Vice-President Eduardo Gallego, Vice-President Congress Affairs Jong Kyung Kim, Executive Officer Bernard Le Guen, Publications Director Christopher Clement, Treasurer Richard Toohey
Website www.irpa.net
IRPA maintains relations with many other international organizations in the field of radiation protection, such as those listed here:
Inter-Governmental Organizations
IAEA- International Atomic Energy Agency
ILO- International Labor Organisation
NEA- Nuclear Energy Agency
UNSCEAR- United Nations Scientific Committee on the Effects of Atomic Radiation
WHO- World Health Organisation
Non-Governmental Organizations
ICNIRP- International Commission on Non-Ionizing Radiation Protection
ICRP- International Commission on Radiological Protection
ICRU- International Commission on Radiation Units and Measurements
ISO- International Organization for Standardization
Professional Organizations
IOMP - International Organization for Medical Physics
ISR - International Society of Radiology
ISRO - International Society for Radiation Oncology
WFNMB - World Federation of Nuclear Medicine and Biology
// (ühesõnaga maailma võimasamad orgnaisatsioonid sellel alal, kellest mitmd usutavasti peavad ka kompartey alla anduma.. kuid eks seda näha)
https://www.sciencedirect.com/science/article/pii/S1665642314705930
Effects of Mobile Phone Radiation onto Human Head with Variation of Holding Cheek and Tilt Positions
https://www.fcc.gov/consumers/guides/specific-absorption-rate-sar-cell-phones-what-it-means-you
https://www.fcc.gov/sites/default/files/sar_for_cell_phones_-_what_it_means_for_you.pdf
Specific Absorption Rate (SAR) For Cell Phones: What It Means For You
What SAR Does Not Show
The SAR value used for FCC approval does not account for the multitude of measurements taken during the testing. Moreover, cell phones constantly vary their power to operate at the minimum power necessary for communications; operation at maximum power occurs infrequently. Consequently, cell phones cannot be reliably compared for their overall exposure characteristics on the basis of a single SAR value for several reasons (each of these examples is based on a reported SAR value for cell phone A that is higher than that for cell phone B):
Cell phone A might have one measurement that was higher than any single measurement for cell phone B. Cell phone A would, therefore, have a higher reported SAR value than cell phone B, even if cell phone B has higher measurements than A in most other locations and/or usage configurations. In such a case, a user generally would receive more RF energy overall from cell phone B.
Cell phone A might communicate more efficiently than cell phone B, so that it operates at lower power than cell phone B would under comparable conditions. Consequently, a user would receive more RF energy overall from cell phone B.
The highest value from cell phone A might come from a position which the user seldom or never employs to hold a phone, whereas that user might usually hold a phone in the position that resulted in the highest value for cell phone B. Therefore, the user would receive the highest RF exposure that cell phone B delivers but would not receive the highest RF exposure that cell phone A delivers.
The Bottom Line
ALL cell phones must meet the FCC’s RF exposure standard, which is set at a level well below that at which laboratory testing indicates, and medical and biological experts generally agree, adverse health effects could occur. For users who are concerned with the adequacy of this standard or who otherwise wish to further reduce their exposure, the most effective means to reduce exposure are to hold the cell phone away from the head or body and to use a speakerphone or hands-free accessory. These measures will generally have much more impact on RF energy absorption than the small difference in SAR between individual cell phones, which, in any event, is an unreliable comparison of RF exposure to consumers, given the variables of individual use.
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https://en.wikipedia.org/wiki/CE_marking
ANEC: " European Association for the Co-ordination of Consumer Representation in Standardisation (known informally as 'the European consumer voice in standardisation') "
"with no independent check of the conformity of the product with EU legislation; ANEC has cautioned that, amongst other things, CE marking cannot be considered a "safety mark" for consumers.
CE marking involves self-certification only in case of minimal risks products. In most cases a notified body must be involved. In these cases the CE mark is followed by the registration number of the Notified body involved in conformity assessment
CE marking was not required by countries of the Central European Free Trade Agreement (CEFTA),
2009:
"A report just published by the GSM Association, the trade body of the mobile phone industry, showed that national self-regulatory codes based on the framework agreement brokered by the European Commission now exist in 22 Member States, 90% of them in line with the 2007 agreement, and 80% of operators have put in place measures to control child access to adult content."
https://ec.europa.eu/commission/presscorner/detail/en/IP_09_596
More on the GSMA report on implementation of the framework agreement on "Safer Mobile Use by Younger Teenagers and Children": http://ec.europa.eu/information_society/activities/sip/self_reg/phones/index_en.htm
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// Thse orgnizatons there is all kinds:
SAR and Mobile Phone Safety
https://amta.org.au/sar/
"he Australian Communications and Media Authority (ACMA) requires industry to comply with the Human Exposure Standard, which applies exposure limits set by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA).
The ARPANSA Standard specifies exposure limits of radiofrequency electromagnetic energy (RF EME) which users absorb from the handset. This is known as the Specific Absorption Rate (SAR), which is the rate at which RF EME is absorbed by body tissue."
AMTA’s response to the Government’s Inquiry into 5G
https://amta.org.au/amtas-response-to-the-governments-inquiry-into-5g/
“ARPANSA’s assessment is that 5G is safe.”
"We therefore called for Government to play a greater role in leading a strategy to work with all levels of government and industry to promote a pathway to 5G including building awareness around the potential benefits of 5G within the public sector itself as well as across industries and enterprise."
// "to promote a pathway to 5G"
What do experts say about 5G and health?
https://amta.org.au/what-do-experts-say-about-5g-and-health/
"In relation to radio frequency exposures and wireless technology and health, including frequencies used for 5G, the World Health Organization (WHO) states: “Despite extensive research, to date there is no evidence to conclude that exposure to low level electromagnetic fields is harmful to human health.”
A Guide to small cells (Australian Communications and Media Authority
https://www.acma.gov.au/theACMA/a-guide-to-small-cells
Australian Radiation Protection and Nuclear Safety Agency (ARPANSA)
https://www.arpansa.gov.au/
EMF Explained (AMTA, GSMA and MWF)
http://www.emfexplained.info/
The Mobile Phone Base Station Deployment Code (Communications Alliance)
http://www.commsalliance.com.au/Documents/all/codes/c564
Research into the health effects of 5G
https://amta.org.au/research-into-the-health-effects-of-5g/
"5G operates at a higher frequency than previous 4G networks so it can carry more data but can’t travel as far. This means it will have less impact on the human body than any previous network. Over 50 years of scientific research has already been conducted into the possible health effects of the radio signals used for mobile phones, base stations and other wireless services including frequencies planned for 5G and mmWave exposures.
ARPANSA states:
“This network currently runs on radio waves similar to those used in the current 4G network, and in the future will use radio waves with higher frequencies. It is important to note that higher frequencies does not mean higher or more intense exposure. Higher frequency radio waves are already used in security screening units at airports, police radar guns to check speed, remote sensors and in medicine and these uses have been thoroughly tested and found to have no negative impacts on human health.”"
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Cell Phone Radiation: Harmful or Not?
Di Lu
June 9, 2012
Submitted as coursework for PH250, Stanford University, Spring 2012
http://large.stanford.edu/courses/2012/ph250/lu1/
"Other effects of RF waves on human body are still not very clear. Some researches show radiofrequency wave can affect the activities of human organs and cells, and even chromosomes. Volkow et al. showed the metabolism rate of brain becomes significantly higher when people are using cell phones (the rate of glucose metabolism increases from 33.3 to 35.7 μmol/100 g per minute). [4] Huber et al. reported 900 MHz RF wave with a peak SAR 1 W/kg can affect the regional cerebral blood flow (rCBF). [5] After a 20-min exposure of RF wave on the left-hand side, the rCBF of the left and right hemisphere of the brain becomes 4.3:0.4. Andrzejak et al. showed during a 20-minutes telephone call with a GSM phone, the standard deviation of human heart rate increases from 74 ms (without cellphones) to 92 ms. [6] J. Miyakoshi et al. showed the treatment of Human Glioma Cells with a 1950 MHz RF field may inhibit the phosphorylation (an important chemical process) of Hsp27 at Serine78 in MO54 cells. [7] Mashevich et al. used 830 MHz electromagnetic fields to treat human peripheral blood lymphocytes (some cells in human body), and found losses and gains of chromosomes increase linearly as the SAR increases from 1.6 to 8.8 W/kg.[8]"
"So far, there are many studies on the danger of RF waves, but no definite conclusion can be made according to these studies. That cell phones can be harmful to human health is just a possibility: it is reported that the WHO considers cell phone radiation as "possibly carcinogenic." [13] Nevertheless, without knowing the mechanism of how RF waves affect human body, it is impossible to answer this question reasonably."
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Radiation Risk: Are Some Cellphones More Dangerous Than Others?
https://www.livescience.com/14755-radiation-risk-cellphones-dangerous.html
Now, some scientists are claiming that certain types of cellphones could be more "possibly carcinogenic" than others.
"I've been telling friends and family members to seriously consider switching to CDMA [cellphones] if they're using GSM cellphones," said Joel Moskowitz, the director of the Center for Family and Community Health at the University of California, Berkeley.
CDMA, or Code Division Multiple Access, is the type of cellular network used by the phone companies Verizon and Sprint. GSM, or Global System for Mobile Communications, is the type used by AT&T and T-Mobile.
There is accumulating evidence that cellphones that operate on GSM networks emit significantly more radiation than do cellphones operating on CDMA networks. This is not apparent when you look at a phone's specs, Moskowitz said, because phone companies are required to list only the "specific absorption rate" (SAR) — the measure of the rate at which energy from a radio frequency electromagnetic field is absorbed by the body — of a phone at its maximum radiation output. "The SAR can be misleading as it measures the maximum radiation a cellphone emits and does not reflect the average amount of radiation it emits," Moskowitz told Life's Little Mysteries.
Several recent studies have shown that CDMA phones normally emit a small fraction of their maximum radiation output, while GSM phones emit, on average, half the maximum, he explained. This comes down to the different radio frequency (RF) bands that the two networks operate on, and the different methods by which the two networks carry phone transmissions.
"When a GSM phone transmits, it immediately goes to the peak power, and then the power control circuitry ratchets down the power to an acceptable level," explained Mark McNeeley, an electrical engineer at Exponent Engineering and Scientific Consulting services and co-author of a recent study comparing GSM and CDMA networks. "CDMA networks share the same frequency among many different phone calls, so all phones transmit at the lowest possible power level necessary to maintain the fidelity of the call." It's like people talking quietly at a party, he said.
The radiation spikes at the beginning of GSM phone calls means that they emit, overall, up to 28 times more radiation than CDMA phones, according to a study co-authored by McNeeley and published last year in the Journal of Exposure Science and Environmental Epidemiology.
There are exceptions. If you have a CDMA phone in a rural area and the nearest CDMA cellphone tower is far away, then you have to broadcast at a radiation level that is equal to or greater than GSM to reach the tower, McNeeley said. If there is a GSM tower much nearer to you, you might be better off going with a GSM network, he said; but in most parts of the country, where both CDMA and GSM towers are ubiquitous, CDMA phones will emit less radiation than GSM phones.
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Although dozens of international studies have been conducted over the past decade, some of which point to higher incidences of certain types of brain cancers in people who use cellphones heavily, the negative side effects of cellphone usage remain undetermined.
Although it's still unclear what that extra brain activity is, how it's caused or whether it's bad, other studies have also shown varying health consequences of using GSM versus CDMA phones. Of 37 studies that have examined GSM phones, 43 percent have found harmful biological effects from the phones — such as a decrease in the expression of genes that help suppress tumors — Moskowitz said, while only 15 percent of the 33 studies that looked at CDMA phones have identified harmful effects.
GSM and CDMA networks work so differently that a phone built for one cannot operate on the other. Furthermore, AT&T and T-Mobile cellular networks, which are GSM, cannot simply switch and become CDMA networks. Given these facts, if you own a GSM phone, should you switch to a carrier that supports CDMA? Experts have mixed opinions.
It is difficult to say whether higher radiation output is bad, simply because the jury is still out on whether cellphone radiation is bad in the first place, says Ken Foster, a professor of bioengineering at the University of Pennsylvania who has been studying the effects of radiofrequencies for 40 years. The radiation level of cellphones — all cellphones — is so low it is considered "non-ionizing." It isn't powerful enough to knock electrons off atoms in cells and potentially change the structure of DNA molecules, which is the way that ionizing radiation (like gamma-rays and X-rays) causes harmful mutations. No one knows by what mechanism non-ionizing radiation, such as RF from cellphones, could possibly damage DNA, Foster says.
Though Foster grants that consumers could probably reduce their exposure by choosing CDMA rather than GSM phones, he doesn't think it's likely a higher radiation output actually makes GSM phones more hazardous than CDMA phones. The radiation levels of both phone types are so low, he said, that there is no known way they could harm DNA.
"If you take a shower at 160 degrees Fahrenheit, that could burn you. But I personally don't fear a shower at 65 degrees Fahrenheit more than one at 63 degrees — neither temperature is dangerous," he said. In his view, cellphone radiation on either type of network is as harmless as two cold showers of slightly different temperatures.
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However, according to other scientists, there is some evidence that the potentially hazardous aspect of cellphone radiation may be the way in which transmissions are modulated — the way individual pulses of radiation are constructed out of a range of frequencies. The modulation pattern is different for CDMA and GSM phones, and some scientists think GSM pulse modulations may have adverse biological effects.
A review article in the April issue of the journal BioElectroMagnetics by Jukka Juutilainen and colleagues at the University of Eastern Finland suggested that specific types of RF modulation may well have biological consequences.
"While the majority of recent studies have reported no modulation-specific effects, there are a few interesting exceptions indicating that there may be specific effects from amplitude-modulated RF fields on the human central nervous system. These findings warrant follow-up studies," the researchers wrote.
According to Moskowitz, the study found that GSM phones contain radiation at a frequency of 8 hertz, or 8 cycles per second, which "is in the range of 'possibly carcinogenic' because our cells have processes on that frequency level, with which the phone radiation may be interfering," he said.
Foster, on the other hand, thinks there is no robust evidence that one type of modulation is more dangerous than the other. "To my knowledge, nothing shows a clear effect of pulse modulation," he said.
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Do some mobile phone networks pose more of a health risk than others? Though some researchers suspect so, it is too soon to say for sure. "Clearly more comparative studies are needed," Moskowitz said.
At this point, all cellphone users should be cautious. "My first recommendation is to keep a safe distance from your phone. Text instead of calling. Use the speakerphone. Use a headset," Moskowitz said. Radiation levels fall off rapidly with distance — so rapidly that you can decrease your brain's exposure to a negligible level simply by keeping your phone antenna just a few inches away.
Moskowitz also thinks people should avoid keeping their cellphones on in their pockets. "There's accumulating evidence of a risk to sperm and male fertility," Moskowitz said. "People are forgetting where they're keeping their cellphones all day long."
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29,209 views•Jan 7, 2011
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