Electromagnetic Radiation And Health
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Electromagnetic radiation In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength ...
can be classified into two types:
ionizing radiation Ionizing (ionising) radiation, including Radioactive decay, nuclear radiation, consists of subatomic particles or electromagnetic waves that have enough energy per individual photon or particle to ionization, ionize atoms or molecules by detaching ...
and
non-ionizing radiation Non-ionizing (or non-ionising) radiation refers to any type of electromagnetic radiation that does not carry enough energy per quantum ( photon energy) to ionize atoms or molecules—that is, to completely remove an electron from an atom or mol ...
, based on the capability of a single
photon A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless particles that can ...
with more than 10  eV energy to ionize atoms or break
chemical bond A chemical bond is the association of atoms or ions to form molecules, crystals, and other structures. The bond may result from the electrostatic force between oppositely charged ions as in ionic bonds or through the sharing of electrons a ...
s.
Extreme ultraviolet Extreme ultraviolet radiation (EUV or XUV) or high-energy ultraviolet radiation is electromagnetic radiation in the part of the electromagnetic spectrum spanning wavelengths shorter than the hydrogen Lyman-alpha line from 121  nm down to ...
and higher frequencies, such as
X-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...
s or
gamma ray A gamma ray, also known as gamma radiation (symbol ), is a penetrating form of electromagnetic radiation arising from high energy interactions like the radioactive decay of atomic nuclei or astronomical events like solar flares. It consists o ...
s are ionizing, and these pose their own special hazards: see '' radiation poisoning''. The
field strength In physics, field strength refers to a value in a vector-valued field (e.g., in volts per meter, V/m, for an electric field ''E''). For example, an electromagnetic field has both electric field strength and magnetic field strength. Field str ...
of electromagnetic radiation is measured in volts per meter (V/m). The most common health hazard of radiation is
sunburn Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, usually from the Sun. Common symptoms in humans and other animals include red or reddish skin tha ...
, which causes between approximately 100,000 and 1 million new skin cancers annually in the United States. In 2011, the
World Health Organization The World Health Organization (WHO) is a list of specialized agencies of the United Nations, specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Gen ...
(WHO) and the
International Agency for Research on Cancer The International Agency for Research on Cancer (IARC; ) is an intergovernmental agency forming part of the World Health Organization of the United Nations. Its role is to conduct and coordinate research into the causes of cancer. It also cance ...
(IARC) have classified radiofrequency electromagnetic fields as possibly
carcinogenic A carcinogen () is any agent that promotes the development of cancer. Carcinogens can include synthetic chemicals, naturally occurring substances, physical agents such as ionizing and non-ionizing radiation, and Biological agent, biologic agent ...
to humans (Group 2B).


Hazards

Dielectric heating Dielectric heating, also known as electronic heating, radio frequency heating, and high-frequency heating, is the process in which a radio frequency (RF) alternating electric field, or radio wave or microwave electromagnetic radiation heats a diel ...
from electromagnetic radiation can create a biological hazard. For example, touching or standing around an antenna while a high-power
transmitter In electronics and telecommunications, a radio transmitter or just transmitter (often abbreviated as XMTR or TX in technical documents) is an electronic device which produces radio waves with an antenna (radio), antenna with the purpose of sig ...
is in operation can cause burns. The mechanism is the same as that used in a
microwave oven A microwave oven, or simply microwave, is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces Dipole#Molecular dipoles, polar molecules in the food to rotate and ...
. The heating effect varies with the power and the
frequency Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...
of the electromagnetic energy, as well as the
inverse square In science, an inverse-square law is any scientific law stating that the observed "intensity" of a specified physical quantity is inversely proportional to the square of the distance from the source of that physical quantity. The fundamental ca ...
of distance to the source. The eyes and testes are particularly susceptible to radio frequency heating due to the paucity of blood flow in these areas that could otherwise dissipate the heat buildup.


Workplace exposure

Radio frequency (RF) energy at power density levels of 1–10 mW/cm2 or higher can cause measurable heating of tissues. Typical RF energy levels encountered by the general public are well below the level needed to cause significant heating, but certain workplace environments near high power RF sources may exceed safe exposure limits. A measure of the heating effect is the
specific absorption rate Specific absorption rate (SAR) is a measure of the rate at which energy is absorbed per unit mass by a human body when exposed to a radio frequency (RF) electromagnetic field. It is defined as the power absorbed per mass of tissue and has unit ...
or SAR, which has units of watts per kilogram (W/kg). The
IEEE The Institute of Electrical and Electronics Engineers (IEEE) is an American 501(c)(3) organization, 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines. The IEEE ...
and many national governments have established safety limits for exposure to various frequencies of electromagnetic energy based on SAR, mainly based on ICNIRP Guidelines, which guard against thermal damage. Industrial installations for induction hardening and melting or on welding equipment may produce considerably higher field strengths and require further examination. If the exposure cannot be determined upon manufacturers' information, comparisons with similar systems or analytical calculations, measurements have to be accomplished. The results of the evaluation help to assess possible hazards to the safety and health of workers and to define protective measures. Since electromagnetic fields may influence passive or active implants of workers, it is essential to consider the exposure at their workplaces separately in the
risk assessment Risk assessment is a process for identifying hazards, potential (future) events which may negatively impact on individuals, assets, and/or the environment because of those hazards, their likelihood and consequences, and actions which can mitigate ...
.


Low-level exposure

The
World Health Organization (WHO) The World Health Organization (WHO) is a specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Geneva, Switzerland, and has 6 regional offices and 15 ...
began a research effort in 1996 to study the health effects from the ever-increasing exposure of people to a diverse range of EMR sources. In 2011, the WHO/International Agency for Research on Cancer (IARC) has classified radio frequency electromagnetic fields as possibly carcinogenic to humans (Group 2B), based on an increased risk for
glioma A glioma is a type of primary tumor that starts in the glial cells of the brain or spinal cord. They are malignant but some are extremely slow to develop. Gliomas comprise about 30% of all brain and central nervous system tumors and 80% of ...
and
acoustic neuroma A vestibular schwannoma (VS), also called acoustic neuroma, is a benign tumor that develops on the vestibulocochlear nerve that passes from the inner ear to the brain. The tumor originates when Schwann cells that form the insulating myelin sheath ...
associated with wireless phone use. The group responsible for the classification did not quantify the risk. Furthermore, group 2B only indicates a credible association between disease and exposure but does not rule out confounding effects with reasonable confidence. A causal relationship has yet to be established. Epidemiological studies look for statistical correlations between EM exposure in the field and specific health effects. As of 2019, much of the current work is focused on the study of EM fields in relation to cancer. There are publications which support the existence of complex biological and neurological effects of weaker ''non-thermal'' electromagnetic fields (see
Bioelectromagnetics Bioelectromagnetics, also known as bioelectromagnetism, is the study of the interaction between electromagnetic fields and biological entities. Areas of study include electromagnetic fields produced by living cells, tissues or organisms, the ...
), including weak
ELF An elf (: elves) is a type of humanoid supernatural being in Germanic peoples, Germanic folklore. Elves appear especially in Norse mythology, North Germanic mythology, being mentioned in the Icelandic ''Poetic Edda'' and the ''Prose Edda'' ...
electromagnetic fields and modulated RF and
microwave Microwave is a form of electromagnetic radiation with wavelengths shorter than other radio waves but longer than infrared waves. Its wavelength ranges from about one meter to one millimeter, corresponding to frequency, frequencies between 300&n ...
fields.


Effects by frequency

While the most acute exposures to harmful levels of electromagnetic radiation are immediately realized as burns, the health effects due to chronic or occupational exposure may not manifest effects for months or years.


Extremely low frequency

Extremely low frequency Extremely low frequency (ELF) is the ITU designation for electromagnetic radiation (radio waves) with frequencies from 3 to 30  Hz, and corresponding wavelengths of 100,000 to 10,000 kilometers, respectively. In atmospheric sc ...
EM waves can span from 0 Hz to 3 kHz, though definitions vary across disciplines. The maximum recommended exposure for the general public is 5 kV/m. ELF waves around 50 Hz to 60 Hz are emitted by
power generator Electricity generation is the process of generating electric power from sources of primary energy. For utilities in the electric power industry, it is the stage prior to its delivery ( transmission, distribution, etc.) to end users or its stora ...
s,
transmission lines In electrical engineering, a transmission line is a specialized cable or other structure designed to conduct electromagnetic waves in a contained manner. The term applies when the conductors are long enough that the wave nature of the transmis ...
and distribution lines,
power cable A power cable is an electrical cable used specifically for transmission of electric energy, electrical power. It is an assembly of one or more electrical conductors, usually held together in a single bundle with an insulator (electricity), insu ...
s, and electric appliances. Typical household exposure to ELF waves ranges in intensity from 5 V/m for a light bulb to 180 V/m for a stereo, measured at and using 240V power. (120V power systems would be unable to reach this intensity unless an appliance has an internal voltage transformer.)
Overhead power line An overhead power line is a structure used in electric power transmission and distribution to transmit electrical energy along large distances. It consists of one or more conductors (commonly multiples of three) suspended by towers or poles. ...
s range from 1kV for local distribution to 1,150 kV for ultra high voltage lines. These can produce electric fields up to 10kV/m on the ground directly underneath, but 50 m to 100 m away these levels return to approximately ambient. Metal equipment must be maintained at a safe distance from energized high-voltage lines. Exposure to ELF waves can induce an electric current. Because the human body is conductive, electric currents and resulting voltages differences typically accumulate on the skin but do not reach interior tissues. People can start to perceive high-voltage charges as tingling when hair or clothing in contact with the skin stands up or vibrates. In scientific tests, only about 10% of people could detect a field intensity in the range of 2-5 kV/m. Such voltage differences can also create electric sparks, similar to a discharge of
static electricity Static electricity is an imbalance of electric charges within or on the surface of a material. The charge remains until it can move away by an electric current or electrical discharge. The word "static" is used to differentiate it from electric ...
when nearly touching a grounded object. When receiving such a shock at 5 kV/m, it was reported as painful by only 7% of test participants and by 50% of participants at 10 kV/m.Extremely Low Frequency Fields Environmental Health Criteria Monograph No.238
chapter 5, p. 121, WHO.
Associations between exposure to extremely low frequency magnetic fields (ELF MF) and various health outcomes have been investigated through a variety of epidemiological studies. A pooled analysis found consistent evidence of an effect of ELF-MF on childhood leukaemia. An assessment of the burden of disease potentially resulting from ELF MF exposure in Europe found that 1.5–2% of childhood leukaemia cases might be attributable to ELF MF, but uncertainties around causal mechanisms and models of dose-response were found to be considerable. The International Agency for Research on Cancer (IARC) finds "inadequate evidence" for human carcinogenicity.


Shortwave

Shortwave Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). There is no official definition of the band range, but it always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (app ...
(1.6 to 30 MHz)
diathermy Diathermy is electrically induced heat or the use of high-frequency electromagnetic currents as a form of physical therapy and in surgical procedures. The earliest observations on the reactions of the human organism to high-frequency electromagn ...
(where EM waves are used to produce heat) can be used as a therapeutic technique for its
analgesic An analgesic drug, also called simply an analgesic, antalgic, pain reliever, or painkiller, is any member of the group of drugs used for pain management. Analgesics are conceptually distinct from anesthetics, which temporarily reduce, and in s ...
effect and deep muscle relaxation, but has largely been replaced by
ultrasound Ultrasound is sound with frequency, frequencies greater than 20 Hertz, kilohertz. This frequency is the approximate upper audible hearing range, limit of human hearing in healthy young adults. The physical principles of acoustic waves apply ...
. Temperatures in muscles can increase by 4–6 °C, and subcutaneous fat by 15 °C. The FCC has restricted the frequencies allowed for medical treatment, and most machines in the US use 27.12 MHz. Shortwave diathermy can be applied in either continuous or pulsed mode. The latter came to prominence because the continuous mode produced too much heating too rapidly, making patients uncomfortable. The technique only heats tissues that are good electrical conductors, such as
blood vessels Blood vessels are the tubular structures of a circulatory system that transport blood throughout many animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the tissues of a body. They also take waste an ...
and
muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...
.
Adipose tissue Adipose tissue (also known as body fat or simply fat) is a loose connective tissue composed mostly of adipocytes. It also contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, Blood vessel, vascular endothel ...
(fat) receives little heating by induction fields because an electrical current is not actually going through the tissues. Studies have been performed on the use of shortwave radiation for cancer therapy and promoting wound healing, with some success. However, at a sufficiently high energy level, shortwave energy can be harmful to human health, potentially causing damage to biological tissues, for example by overheating or inducing electrical currents. The FCC limits for maximum permissible workplace exposure to shortwave radio frequency energy in the range of 3–30 MHz has a plane-wave equivalent
power density Power density, defined as the amount of power (the time rate of energy transfer) per unit volume, is a critical parameter used across a spectrum of scientific and engineering disciplines. This metric, typically denoted in watts per cubic meter ...
of where is the frequency in MHz, and 100 mW/cm2 from 0.3 to 3.0 MHz. For uncontrolled exposure to the general public, the limit is between 1.34 and 30 MHz.


Radio and microwave frequencies

The classification of mobile phone signals as "possibly
carcinogen A carcinogen () is any agent that promotes the development of cancer. Carcinogens can include synthetic chemicals, naturally occurring substances, physical agents such as ionizing and non-ionizing radiation, and biologic agents such as viruse ...
ic to humans" by the
World Health Organization The World Health Organization (WHO) is a list of specialized agencies of the United Nations, specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Gen ...
(WHO)"a positive association has been observed between exposure to the agent and cancer for which a causal interpretation is considered by the Working Group to be credible, but chance, bias or confounding could not be ruled out with reasonable confidence"has been interpreted to mean that there is very little scientific evidence as to phone signal carcinogenesis. In 2011, the International Agency for Research on Cancer (IARC) classified mobile phone radiation as group 2B, "possibly carcinogenic," rather than group 2A ("probably carcinogenic") or
group 1 Group 1 may refer to: * Alkali metal, a chemical element classification for Alkali metal * Group 1 (motorsport), a regulation set of the FIA for series-production touring cars used in motorsport. * Group One Thoroughbred horse races, the leading e ...
("is carcinogenic"). That means that there "could be some risk" of carcinogenicity, so additional research into the long-term, heavy use of mobile phones needs to be conducted. The
WHO The World Health Organization (WHO) is a specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Geneva, Switzerland, and has 6 regional offices and 15 ...
concluded in 2014 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." Since 1962, the microwave auditory effect or tinnitus has been shown from radio frequency exposure at levels below significant heating. Studies during the 1960s in Europe and Russia claimed to show effects on humans, especially the nervous system, from low energy RF radiation; the studies were disputed at the time. In 2019, reporters from the
Chicago Tribune The ''Chicago Tribune'' is an American daily newspaper based in Chicago, Illinois, United States. Founded in 1847, it was formerly self-styled as the "World's Greatest Newspaper", a slogan from which its once integrated WGN (AM), WGN radio and ...
tested the level of radiation from smartphones and found that certain models emitted more than reported by the manufacturers and in some cases more than the U.S.
Federal Communications Commission The Federal Communications Commission (FCC) is an independent agency of the United States government that regulates communications by radio, television, wire, internet, wi-fi, satellite, and cable across the United States. The FCC maintains j ...
exposure limit. It is unclear if this resulted in any harm to consumers. Some problems apparently involved the phone's ability to detect proximity to a human body and lower the radio power. In response, the FCC began testing some phones itself rather than relying solely on manufacturer certifications.
Microwave Microwave is a form of electromagnetic radiation with wavelengths shorter than other radio waves but longer than infrared waves. Its wavelength ranges from about one meter to one millimeter, corresponding to frequency, frequencies between 300&n ...
and other radio frequencies cause heating, and this can cause
burns Burns may refer to: Astronomy * 2708 Burns, an asteroid * Burns (crater), on Mercury People * Burns (surname), list of people and characters named Burns ** Burns (musician), Scottish record producer Places in the United States * Burns, ...
or eye damage if delivered in high intensity, or
hyperthermia Hyperthermia, also known as overheating, is a condition in which an individual's body temperature is elevated beyond normal due to failed thermoregulation. The person's body produces or absorbs more heat than it dissipates. When extreme te ...
as with any powerful heat source.
Microwave oven A microwave oven, or simply microwave, is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces Dipole#Molecular dipoles, polar molecules in the food to rotate and ...
s use this form of radiation, and have shielding to prevent it from leaking out and unintentionally heating nearby objects or people.


Millimeter waves

In 2009, the US TSA introduced full-body scanners as a primary screening modality in
airport security Airport security includes the techniques and methods used in an attempt to protect passengers, staff, aircraft, and airport property from malicious harm, crime, terrorism, and other threats. Aviation security is a combination of measures and hum ...
, first as backscatter X-ray scanners, which use ionizing radiation and which the European Union banned in 2011 due to health and safety concerns. These were followed by non-ionizing
millimeter wave scanner A millimeter wave scanner is a whole-body imaging device used for detecting objects concealed underneath a person’s clothing using a form of electromagnetic radiation. Typical uses for this technology include detection of items for commercial ...
s. Likewise
WiGig WiGig, alternatively known as 60 GHz Wi-Fi, refers to a set of V band, 60 GHz wireless network protocols. It includes the current IEEE 802.11ad standard and also the IEEE 802.11ay standard. The WiGig specification allows devices to co ...
for
personal area network A personal area network (PAN) is a computer network for interconnecting electronic devices within an individual person's workspace. A PAN provides data transmission among devices such as computers, smartphones, tablets and personal digital assi ...
s have opened the 60 GHz and above microwave band to SAR exposure regulations. Previously, microwave applications in these bands were for point-to-point satellite communication with minimal human exposure.


Infrared

Infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...
wavelengths longer than 750 nm can produce changes in the lens of the eye. Glassblower's cataract is an example of a heat injury that damages the anterior lens capsule among unprotected glass and iron workers. Cataract-like changes can occur in workers who observe glowing masses of glass or iron without protective eyewear for prolonged periods over many years. Exposing skin to infrared radiation near visible light (IR-A) leads to increased production of
free radicals In chemistry, a radical, also known as a free radical, is an atom, molecule, or ion that has at least one unpaired electron, unpaired valence electron. With some exceptions, these unpaired electrons make radicals highly chemical reaction, chemi ...
. Short-term exposure can be beneficial (activating protective responses), while prolonged exposure can lead to
photoaging Photoaging or photoageing (also known as "dermatoheliosis") is a term used for the characteristic changes to skin induced by chronic Ultraviolet, UVA and UVB exposure. Effects of UV light Molecular and genetic changes UVB rays are a primary ...
. Another important factor is the distance between the worker and the source of radiation. In the case of
arc welding Arc welding is a welding process that is used to join metal to metal by using electricity to create enough heat to melt metal, and the melted metals, when cool, result in a joining of the metals. It is a type of welding that uses a welding power ...
, infrared radiation decreases rapidly as a function of distance, so that farther than three feet away from where welding takes place, it does not pose an ocular hazard anymore but, ultraviolet radiation still does. This is why welders wear tinted glasses and surrounding workers only have to wear clear ones that filter UV.


Visible light

Photic retinopathy is damage to the macular area of the eye's retina that results from prolonged exposure to sunlight, particularly with dilated pupils. This can happen, for example, while observing a
solar eclipse A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby obscuring the view of the Sun from a small part of Earth, totally or partially. Such an alignment occurs approximately every six months, during the eclipse season i ...
without suitable eye protection. The Sun's radiation creates a photochemical reaction that can result in visual dazzling and a
scotoma A scotoma is an area of partial alteration in the field of vision consisting of a partially diminished or entirely degenerated visual acuity that is surrounded by a field of normal – or relatively well-preserved – vision. Every normal mamm ...
. The initial lesions and
edema Edema (American English), also spelled oedema (British English), and also known as fluid retention, swelling, dropsy and hydropsy, is the build-up of fluid in the body's tissue (biology), tissue. Most commonly, the legs or arms are affected. S ...
will disappear after several weeks, but may leave behind a permanent reduction in visual acuity. Moderate and high-power lasers are potentially hazardous because they can burn the
retina The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional ...
of the eye, or even the
skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...
. To control the risk of injury, various specifications – for example ANSI Z136 in the US, EN 60825-1/A2 in Europe, and IEC 60825 internationally – define "classes" of lasers depending on their power and wavelength. Regulations prescribe required safety measures, such as labeling lasers with specific warnings, and wearing laser safety goggles during operation (see laser safety). As with its infrared and ultraviolet radiation dangers, welding creates an intense brightness in the visible light spectrum, which may cause temporary flash blindness. Some sources state that there is no minimum safe distance for exposure to these radiation emissions without adequate eye protection.


Ultraviolet

Sunlight includes sufficient ultraviolet power to cause
sunburn Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, usually from the Sun. Common symptoms in humans and other animals include red or reddish skin tha ...
within hours of exposure, and the burn severity increases with the duration of exposure. This effect is a response of the skin called
erythema Erythema (, ) is redness of the skin or mucous membranes, caused by hyperemia (increased blood flow) in superficial capillaries. It occurs with any skin injury, infection, or inflammation. Examples of erythema not associated with pathology inc ...
, which is caused by a sufficient strong dose of
UV-B Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of th ...
. The Sun's UV output is divided into
UV-A Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of the ...
and UV-B: solar UV-A flux is 100 times that of UV-B, but the erythema response is 1,000 times higher for UV-B. This exposure can increase at higher altitudes and when reflected by snow, ice, or sand. The UV-B flux is 2–4 times greater during the middle 4–6 hours of the day, and is not significantly absorbed by cloud cover or up to a meter of water. Ultraviolet light, specifically UV-B, has been shown to cause
cataracts A cataract is a cloudy area in the lens of the eye that leads to a decrease in vision of the eye. Cataracts often develop slowly and can affect one or both eyes. Symptoms may include faded colours, blurry or double vision, halos around ligh ...
and there is some evidence that sunglasses worn at an early age can slow its development in later life. Most UV light from the sun is filtered out by the atmosphere and consequently airline pilots often have high rates of cataracts because of the increased levels of UV radiation in the upper atmosphere. It is hypothesized that depletion of the ozone layer and a consequent increase in levels of UV light on the ground may increase future rates of cataracts. Note that the lens filters UV light, so if it is removed via surgery, one may be able to see UV light. Prolonged exposure to
ultraviolet radiation Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of t ...
from the
sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...
can lead to
melanoma Melanoma is the most dangerous type of skin cancer; it develops from the melanin-producing cells known as melanocytes. It typically occurs in the skin, but may rarely occur in the mouth, intestines, or eye (uveal melanoma). In very rare case ...
and other skin malignancies. Clear evidence establishes ultraviolet radiation, especially the non-ionizing medium wave
UVB Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of the ...
, as the cause of most non-melanoma
skin cancer Skin cancers are cancers that arise from the Human skin, skin. They are due to the development of abnormal cells (biology), cells that have the ability to invade or metastasis, spread to other parts of the body. It occurs when skin cells grow ...
s, which are the most common forms of cancer in the world. UV rays can also cause wrinkles,
liver spot Liver spots (also known as age spot, solar lentigo, "lentigo senilis", "old age spot", "senile freckle") are wikt:blemish, blemishes on the skin associated with aging and exposure to ultraviolet, ultraviolet radiation from the sun. They range in c ...
s, moles, and
freckles Freckles are clusters of concentrated melaninized cells which are most easily visible on people with a fair complexion. Freckles do not have an increased number of the melanin-producing cells, or melanocytes, but instead have melanocytes that ...
. In addition to sunlight, other sources include tanning beds, and bright desk lights. Damage is cumulative over one's lifetime, so that permanent effects may not be evident for some time after exposure. Ultraviolet radiation of wavelengths shorter than 300 nm ( actinic rays) can damage the corneal epithelium. This is most commonly the result of exposure to the sun at high altitude, and in areas where shorter wavelengths are readily reflected from bright surfaces, such as snow, water, and sand. UV generated by a
welding Welding is a fabrication (metal), fabrication process that joins materials, usually metals or thermoplastics, primarily by using high temperature to melting, melt the parts together and allow them to cool, causing Fusion welding, fusion. Co ...
arc can similarly cause damage to the cornea, known as "arc eye" or welding flash burn, a form of
photokeratitis Photokeratitis or ultraviolet keratitis is a painful eye condition caused by exposure of insufficiently protected eyes to the ultraviolet (UV) rays from either natural (e.g. intense direct or reflected sunlight) or artificial (e.g. the electri ...
.
Fluorescent light A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, to produce ultraviolet and make a phosphor ...
bulbs and tubes internally produce
ultraviolet Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of ...
light. Normally this is converted to visible light by the
phosphor A phosphor is a substance that exhibits the phenomenon of luminescence; it emits light when exposed to some type of radiant energy. The term is used both for fluorescent or phosphorescent substances which glow on exposure to ultraviolet or ...
film inside a protective coating. When the film is cracked by mishandling or faulty manufacturing then UV may escape at levels that could cause sunburn or even skin cancer.


Regulation

In the United States, non-ionizing radiation is regulated in the Radiation Control for Health and Safety Act of 1968 and the
Occupational Safety and Health Act of 1970 The Occupational Safety and Health Act of 1970 is a US labor law governing the federal law of occupational health and safety in the private sector and federal government in the United States. It was enacted by Congress in 1970 and was signed by ...
. In Canada, various federal acts govern non-ionizing radiation by originating source, such as the Radiation Emitting Devices Act, the Canada Consumer Product Safety Act, and the Radiocommunication Act. For situations not under federal jurisdiction, Canadian provinces individually set regulations around use of non-ionizing radiation.


See also

* Background radiation * Bioinitiative Report *
Biological effects of radiation on the epigenome Ionizing radiation can cause biological effects which are passed on to offspring through the epigenome. The radiobiology, effects of radiation on cells has been found to be dependent on the Radiation dose, dosage of the radiation, the location of t ...
* Central nervous system effects from radiation exposure during spaceflight *
Cosmic ray Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the ...
*
COSMOS cohort study COSMOS is a cohort study of mobile phone use and health. The study will investigate the possible health effects of long-term use of mobile phones and other wireless technologies. It is an international study being conducted in five European countr ...
*
Directed energy weapon A directed-energy weapon (DEW) is a ranged weapon that damages its target with highly focused energy without a solid projectile, including lasers, microwaves, particle beams, and sound beams. Potential applications of this technology include w ...
* Electromagnetic hypersensitivity *
Electromagnetism In physics, electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. The electromagnetic force is one of the four fundamental forces of nature. It is the dominant force in the interacti ...
* EMF measurement * Health threat from cosmic rays * Light ergonomics * Magnetobiology *
Microwave Microwave is a form of electromagnetic radiation with wavelengths shorter than other radio waves but longer than infrared waves. Its wavelength ranges from about one meter to one millimeter, corresponding to frequency, frequencies between 300&n ...
* Wireless device radiation and health * Personal RF safety monitor *
Specific absorption rate Specific absorption rate (SAR) is a measure of the rate at which energy is absorbed per unit mass by a human body when exposed to a radio frequency (RF) electromagnetic field. It is defined as the power absorbed per mass of tissue and has unit ...


References


Further reading

* (over 100 pages)


External links


Information page
on electromagnetic fields at the
World Health Organization The World Health Organization (WHO) is a list of specialized agencies of the United Nations, specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Gen ...
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CDC – Electric and Magnetic Fields – NIOSH Workplace Safety and Health Topic
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Biological Effects of Power Frequency Electric and Magnetic Fields (May 1989)
(110 pages) prepared for US Congress Office of Technology Assessment by Indira Nair, M.Granger Morgan, Keith Florig, Department of Engineering and Public Policy Carnegie Mellon University {{DEFAULTSORT:Electromagnetic Radiation And Health Environmental controversies Medical physics Radiation health effects Radiobiology Health effects by subject