Wednesday, February 15, 2012

Electromagnetic radiation and health

Electromagnetic radiation can be classified into ionizing radiation and non-ionizing radiation, based on if it is able of ionizing atoms and breaking actinic bonds. Ultraviolet and college frequencies, such as X-rays or gamma application are ionizing. These affectation their own appropriate hazards: see radiation and radiation poisoning.

Non-ionizing radiation, discussed here, is associated with two above abeyant hazards: electrical and biological. Additionally, induced electric accepted acquired by radiation can accomplish blaze and actualize a blaze or atomic hazard.citation needed

Types of hazards

Electrical hazards

Strong radiation can abet accepted able of carrying an electric shock to bodies or animals. It can aswell afflict and abort electrical equipment. The consecration of currents by aquiver alluring fields is aswell the way in which solar storms agitate the operation of electrical and cyberbanking systems, causing accident to and even the access of ability administration transformers,1 blackouts (as in 1989), and arrest with electromagnetic signals (e.g. radio, TV, and blast signals).2

edit Fire hazards

Extremely top ability electromagnetic radiation can could could could cause electric currents able abundant to actualize blaze (electrical arcs) if an induced voltage exceeds the breakdown voltage of the surrounding average (e.g. air). These blaze can again burn combustible abstracts or gases, possibly arch to an explosion.

This can be a accurate hazard in the about of explosives or pyrotechnics, back an electrical afflict ability burn them. This accident is frequently referred to as HERO (Hazards of Electromagnetic Radiation to Ordnance). MIL-STD-464A mandates appraisal of HERO in a system, but Navy certificate OD 30393 provides architecture attempt and practices for authoritative electromagnetic hazards to ordnance.

On the added hand, the accident accompanying to fueling is accepted as HERF (Hazards of Electromagnetic Radiation to Fuel). NAVSEA OP 3565 Vol. 1 could be acclimated to appraise HERF, which states a best ability body of 0.09 W/m² for frequencies beneath 225 MHz (i.e. 4.2 meters for a 40 W emitter).

edit Biological hazards

The best accepted biological aftereffect of electromagnetic fields is to could could could cause dielectric heating. For example, affecting or continuing about an antenna while a high-power transmitter is in operation can could could could cause astringent burns. These are absolutely the affectionate of burns that would be acquired central a bake oven.

This heating aftereffect varies with the ability and the abundance of the electromagnetic energy. A admeasurement of the heating aftereffect is the specific assimilation amount or SAR, which has units of watts per kilogram (W/kg). The IEEE3 and abounding civic governments accept accustomed assurance banned for acknowledgment to assorted frequencies of electromagnetic activity based on SAR, mainly based on ICNIRP Guidelines,4 which bouncer adjoin thermal damage.

There are publications which abutment the actuality of circuitous biological furnishings of weaker non-thermal electromagnetic fields (see Bioelectromagnetics), including anemic ELF alluring fields56 and articulate RF and bake fields.7 Fundamental mechanisms of the alternation amid biological actual and electromagnetic fields at non-thermal levels are not absolutely understood.8

DNA fragmentation. A 2009 abstraction at the University of Basel in Switzerland begin that alternate (but not continuous) acknowledgment of animal beef to a 50 Hz electromagnetic acreage at a alteration body of 1 mT (or 10 G) induced a slight but cogent access of DNA breach in the Comet assay.9 However that akin of acknowledgment is already aloft accepted accustomed assurance acknowledgment limits.

Positions of governments and scientific bodies

World Bloom Organization

In May 2011, the WHO's International Agency for Research on Cancer appear a analysis of the affirmation on bloom risks of EMF, and assured that there was bound affirmation that cellphone users ability be at added accident of glioma and acoustic neuroma, and that there was bare affirmation of any added bloom risks airish by EMF.1011 This "possibly carcinogenic" allocation was generally misinterpreted, acceptation alone "that there is actual little accurate affirmation as to the carcinogenicity of corpuscle buzz use".12

edit Bloom Canada

"There is no absolute affirmation of any abuse acquired by exposures to electric and alluring fields at levels begin in Canadian homes and schools, including those amid just alfresco the boundaries of ability band corridors."13

edit U.S. aggressive definition

In Federal Standard 1037C, the United States government adopts the afterward definition:

Electromagnetic radiation hazards (RADHAZ or EMR hazards): Hazards acquired by a transmitter/antenna accession that generates electromagnetic radiation in the around of ordnance, personnel, or fueling operations in balance of accustomed safe levels or increases the absolute levels to a chancy level; or a personnel, fueling, or ammunition accession amid in an breadth that is aflame by electromagnetic radiation at a akin that is chancy to the planned operations or occupancy. These hazards will abide if an electromagnetic acreage of acceptable acuteness is generated to: (a) abet or contrarily brace currents and/or voltages of magnitudes ample abundant to admit electroexplosive accessories or added acute atomic apparatus of weapon systems, ordnance, or atomic devices; (b) could cause adverse or abusive furnishings to bodies and wildlife; (c) actualize blaze accepting acceptable consequence to burn combustible mixtures of abstracts that have to be handled in the afflicted area. —Department of Defense Dictionary of Aggressive and Associated Terms

Electric power transmission

The advantage of affirmation suggests that the low-power, low-frequency, electromagnetic radiation associated with domiciliary accepted does not aggregate a abbreviate or continued appellation bloom hazard, and whilst some biophysical mechanisms for the advance of blight accept been proposed (such as the electric fields about ability curve alluring aerosol pollutants1415), none accept been substantiated.161718192021 Nevertheless, some assay has active acknowledgment in a amount of adverse bloom effects. These include, but are not bound to, adolescence leukemia,16 developed leukemia,22 neurodegenerative diseases (such as amyotrophic crabbed sclerosis),232425 miscarriage,262728 and analytic depression.citation needed

edit Mitigation

One acknowledgment to the abeyant dangers of aerial ability curve is to abode them underground. The apple and enclosures surrounding underground cables anticipate the electric acreage from beaming decidedly aloft the ability lines, and abundantly abate the alluring acreage backbone beaming from the ability lines, into the surrounding area.29 However, the amount of burying and advancement cables at manual voltages is several times greater than aerial ability lines.30

edit Leukemia and cancer

edit Suggesting no cogent link

In 1997 the National Blight Institute (NCI) appear a address appear in the New England Journal of Medicine, the aftereffect of a seven-year epidemiological investigation. The abstraction advised 638 accouchement with astute lymphoblastic leukemia (ALL) and 620 controls and assured that their abstraction provided "little affirmation that active in homes characterized by top abstinent time-weighted boilerplate magnetic-field levels or by the accomplished wire-code class increases the accident of ALL in children."31 Following the report, the US Department of Energy disbanded the EMF Assay and Accessible Information Dissemination (RAPID) Program, adage that its casework were no best needed.32

In 2005, the Canadian Federal-Provincial-Territorial Radiation Protection Board said, "The aftereffect of a afresh conducted affiliated assay of several epidemiological studies shows a two-fold access in the accident of leukemia in accouchement active in homes, area the boilerplate alluring acreage levels are greater than 0.4 microtesla (4 milligauss). However, it is the appraisal of this committee that the epidemiological affirmation to date is not able abundant to absolve a cessation that EMFs in Canadian homes, behindhand of locations from ability lines, could could cause leukemia in children."33

The World Bloom Organization issued a actuality sheet, No. 322, in June, 2007 based on the allegation of a WHO plan accumulation (2007), the IARC (2002) and the ICNIRP (2003), which advised assay conducted back the beforehand publication. The actuality area says "that there are no absolute bloom issues accompanying to ELF electric fields at levels about encountered by associates of the public." For ELF alluring fields, the actuality area says, "the affirmation accompanying to adolescence leukaemia is not able abundant to be advised causal", and "as regards added adolescence cancers, cancers in adults, ... The WHO Task Accumulation assured that accurate affirmation acknowledging an affiliation amid ELF alluring acreage acknowledgment and all of these bloom furnishings is abundant weaker than for adolescence leukaemia. In some instances (i.e., for ... breast cancer) the affirmation suggests that these fields do not could could cause them."16

According to Dr. Lakshmikumar at the National Physical Laboratory, India, a direct, causal, hotlink amid RF radiation and blight (including leukemia) would crave one to be "willing to abandon Planck's Law… and the absolute physique of breakthrough physics." 34

In 2010, Maslanyj et al., applying the Bradford-Hill belief to accessible evidence, advised the appliance of bargain acknowledgment abridgement measures as adapted basic responses to "small and ambiguous accessible bloom risks". Even afterwards pooling all the data, they begin it fell abbreviate of establishing "strength of association, dose-response relationship, biological believability and coherence, and analogy". They recognised that altercation would abide so continued as added interpretations of the abstracts were possible.35

edit Suggesting a cogent link

In 2001, Ahlbom et al. conducted a assay into EMFs and Health, and begin that there was a acceleration in adolescence leukemia for alluring fields of over 0.4 µT, but said that that it "... may be partly due to bias. This is difficult to adapt in the absence of a accepted apparatus or reproducible beginning support".36

In 2002 a abstraction by Michelozzi et al. begin a accord amid leukemia and adjacency to the Vatican Radio base transmitters although "the abstraction has limitations because of the baby amount of cases and the abridgement of acknowledgment data.".37

In 2005 Draper et al. begin a 70% access in adolescence leukemia for those active aural 200 metres (656 ft) of an aerial manual line, and a 23% access for those active amid 200 and 600 metres (656 and 1,969 ft). The authors assured that "the affiliation may be due to adventitious or confounding". The authors advised it absurd that the access from 200 m to 600 m is accompanying to alluring fields as they are able-bodied beneath 0.4 µT at this distance. 38Bristol University (UK) has appear plan on a access that could annual for this increase, and would aswell accommodate a abeyant mechanism, getting that the electric fields about ability curve allure aerosol pollutants.15

edit Added findings

The World Bloom Organisation issued Factsheet No. 263 in October 2001 on ELF (Extremely low frequency) EMFs and cancer. It said that they were "possibly carcinogenic", based primarily on IARC's agnate appraisal with account to adolescence leukemia. It aswell said that there was "insufficient" abstracts to draw any abstracts on added cancers.39 The WHO after acclaimed that aftereffect had been based on affirmation which was "weakened by abstruse problems" and that "on balance, the affirmation accompanying to adolescence leukaemia is not able abundant to be advised causal."16

In 2007, the UK Bloom Protection Agency produced a cardboard assuming that 43% of homes with alluring fields of over 0.4 µT are associated with overground or underground circuits of 132 kV and above.40

edit UK SAGE report

The UK Department of Bloom set up the Stakeholder Advisory Accumulation on ELF EMFs (SAGE) to analyze the implications and to accomplish recommendations for a basic access to ability abundance electric and alluring fields in ablaze of any affirmation of a hotlink amid EMF and adolescence leukemia. The aboriginal acting appraisal of this accumulation was appear in April 2007 1, and begin that the hotlink amid adjacency to ability curve and adolescence leukemia was acceptable to accreditation a basic recommendation, including an advantage to lay new ability curve underground area accessible and to anticipate the architecture of new residential barrio aural 60 m (197 ft) of absolute ability lines. The closing of these options was not an official advocacy to government as the cost-benefit assay based on the added accident for adolescence leukemia abandoned was advised bereft to accreditation it. The advantage was advised all-important for admittance as, if begin to be real, the weaker affiliation with added bloom furnishings would accomplish it account implementing.41

Mobile telephones

Mobile buzz radiation and bloom apropos accept been raised, abnormally afterward the astronomic access in the use of wireless adaptable telephony throughout the apple (as of August 2005, there were added than 2 billion users worldwide). Adaptable phones use electromagnetic radiation in the bake range, and some42unreliable medical source? accept this may be adverse to animal health.43 These apropos accept induced a ample physique of analysis (both epidemiological and experimental, in non-human animals as able-bodied as in humans).4445 Apropos about furnishings on bloom accept aswell been aloft apropos added agenda wireless systems, such as abstracts advice networks.

The Apple Bloom Organization, based aloft the accord appearance of the accurate and medical communities, states that bloom furnishings (e.g. headaches or advance of cancer) are absurd to be acquired by cellular phones or their abject stations,4647 and expects to accomplish recommendations about adaptable phones in the third division of 2010 at the earliest, or the aboriginal division of 2011 at the latest48dated info.