Radiation-Emitting Household Appliances
Radiation-Emitting Household Appliances
Do TV screens emit radiation?
In addressing this issue one must distinguish between different types of TV screens. The new generations of flat TV screens (LCD or LED) typically consume little energy, and the level of exposure to radiation emitted by them is significantly lower than that of the old type.
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flat TV screen |
Vintage TV |
The guiding principle in discussing exposure to non-ionizing radiation is the precautionary principle, which calls for taking simple measures to reduce exposure to the minimal level necessary for efficient and safe use of the given technology, in particular by increasing the distance between the body and the source of radiation .
TV screens based on the old technology consume a relatively high energy electric current, so that they produce magnetic fields of relatively high power in their immediate vicinity. With the new types of screen, the level of exposure to non-ionizing radiation is relatively low, and does not exceed the above recommendation. Conversely, with the older type of screen, one should maintain a certain distance from the screen, based on the principle outlined above.
If a level of radiation higher than the permitted one is suspected, it may be measured by authorized inspectors specialized in ELF radiation. These experts are listed on the website of the Ministry for Environmental Protection (Hebrew).
22.10.2015
Are there recommendations regarding the use and placement of electromagnetic radiation-emitting devices during sleep?
The level of exposure to non-ionizing radiation decreases significantly with the distance between the human body and the source of radiation. Therefore, it is recommended not to place radiation-emitting devices that have a fixed location (such as routers, mobile phone chargers, supports for cordless phones) in rooms where one spends many hours, such as bedrooms. If there are electrical and other appliances in the bedroom (such as TV, computer, adjustable bed) they should be placed as far as possible from the bed and/or switched off /disconnected during sleep.
25.10.15
Are there recommendations regarding the use of Wi-Fi networks in private homes?
In general, the level of radiation measured during the use of Wi-Fi is low. The maximal transmission output of a typical cordless home router is about 100 milli-watts, and at a distance of 1 meter from it the level is only about 1 micro-watts/cm2. This level is only 1% of the recommended threshold in Israel for exposure to transmission at the recognized frequency for the Wi-Fi network. Modern forms of routers and mobile phones emit levels lower than this, and may drop to a level of 20 milli-watts.
When using laptops or mobile phones connected to the Wi-Fi network, the individual exposure to radiation emitted by the device is greater, because of its proximity to the body: at a distance of 30 cm the maximal exposure is about 9 micro-watts/cm2. This is an exposure additional to that emitted by the cordless router. In general, the recommended threshold value for exposure to any source of transmission at Wi-Fi frequency is 100 micro-watts/cm2, in accordance with the recommendations of the Ministry of Health and the Ministry of Environmental Protection.
As mentioned under placement of devices during sleep, it is best not to place the cordless router in the bedroom near the bed, or in any room where one spends many hours consecutively near the device. It is also possible to disconnect the transmission from the router while the Wi-Fi network is not in use, such as at night.
26.10.2015
At home, is it preferable to use a cordless phone rather than a mobile phone? Does the cordless phone emit more radiation when not resting on its support?
The home cordless phone transmits signals to its base in order to route a conversation outwards, thus emitting non-ionizing radiation. In general, cordless phones have a significantly lower output than that of mobile phones. Since the distance between the phone and its support is relatively small, there is no need for a high intensity of transmission, and the level of radiation is consequently low.
When the handset is not placed in its base and not in call mode, the emitted radiofrequency radiation is relatively low (compared to during a conversation). There are some models where the transmitters are switched off during the non-call mode, thus not emitting any radiation until a call is initiated.
When the phone is placed in its base, the radiofrequency communication channel is usually disconnected and therefore does not emit any radiofrequency radiation, but there are some devices that do not disconnect the communication channel in this mode.
It may thus be concluded that in general, the level of radiation emitted by cordless phones is lower than that from mobile phones.
It should be noted that the newer cellular networks adapt the emitted radiation to the location of the device and to the technological profile of the network. Therefore, the mobile phone may adapt the intensity to the lowest possible level of radiation, so that the radiation emitted by the mobile phone may in fact be lower than that of the home cordless phone.
26.10.15
Is there a risk of exposure to radiation from the home desktop computer?
The desktop computer is a source of two types of non-ionizing radiation exposure:
- Extremely low frequency (ELF) emitted from the computer as an electric device.
- Radiofrequency radiation (RF) emitted from the wireless router when the computer is connected to a WiFi network.
Both types of radiation – ELF from the electric grid and RF from the wireless router have been classified by the World Health Organization as possibly carcinogenic to humans (category 2B).
Radiation from the electric grid:
Electricity is supplied to a desktop computer through the power supply from the electric grid. The computer board and the computer's various components operate by a direct current at low voltage. The computer's transformer converts the high electric voltage from the electric grid to low voltage. The electric currents of the transformer create a relatively strong magnetic field, usually a few tens of milligauss, in its close vicinity (a few tens of centimeters up to one meter). The magnetic field intensity decreases rapidly with distance, to a background level of the typical magnetic field in the home (in an average home the level of exposure is about 1 milligauss).
It is recommended that the user should be situated at least 50 cm from the computer's power supply.
Regarding RF radiation from the wireless router, the answer can be found under "Are there recommendations relating to the use of Wi-Fi networks in private homes?"
30.3.16
How can a microwave oven be used safely?
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Microwave ovens heat and cook food by microwave radiation that causes food molecules, and especially water molecules, to rotate thereby generating heat. When the microwave oven's door is closed, the oven's chamber becomes a Faraday cage (a closed chamber that is impenetrable to electric fields, named after the physicist Michael Faraday). The microwave oven door is made of glass but is shielded by an iron screen, preventing radiation from escaping the closed chamber.
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As long as the microwave oven is undamaged, that is, the microwave oven door is sealed, closes correctly and there are no holes in the door's screen, it is safe to use the oven and remain in its vicinity.
If there is concern that the microwave oven is faulty. For example, if the door is not sealed, there is a hole in the door's iron screen or in the oven's chamber, it is recommended not to use it.
When the microwave oven is operating it is recommended, as a safety precaution, to be at a distance of 50-100 cm from it.
A Ministry of Environmental Protection-authorized radiofrequency inspector can check the intactness of the microwave oven. For your convenience a list of approved inspectors for conducting measurements of non-ionizing radiation may be found in the following link: http://www.sviva.gov.il/subjectsEnv/Radiation/measurements/Pages/default.aspx
8.6.16
Do underfloor heating systems cause exposure to non-ionizing radiation?
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Underfloor heating consists of an electric wire grid that is installed under the floor tiles. An electric current passing through the wires, heats them and the heat is transferred to the floor thereby warming the room. |
Underfloor electric heating systems |
Single wire element underfloor heating was manufactured and sold in Israel until a few years ago. In this type of underfloor heating system, the wire leading the current in one direction and the returning wire leading the current in the opposite direction are placed relatively far apart from one another. In this configuration, a high-intensity magnetic field (of up to 200 mG and higher in close proximity to the wires, depending on the depth of the installation of the heating system and on the level at which the measurements were carried out) is created which cannot be cancelled out by the magnetic field of the returning wire.
Following an intervention by the Ministry of Environmental Protection, nowadays dual wire underfloor heating systems are manufactured and sold in Israel. In this type of system the wire leading the current in one direction and the returning wire are adjacent so that the magnetic field created by one wire is cancelled out by the magnetic field of the returning wire. With this type of system, the magnetic field formed above the floor is very low (assuming that it is optimally installed).
In addition to having electric currents and magnetic fields, underfloor heating systems are also characterized by long operating times, thereby leading to long-term exposure to magnetic fields compared to exposure to other domestic electric appliances.
If you are intending to install an underfloor heating system, to minimize the exposure to magnetic fields, plan well in advance and ensure that a dual core element system has been placed optimally prior to laying the floors.
If you have an old underfloor heating system, it is possible to minimize the time of exposure by turning the system on before people enter the room, turning it off when the temperature is pleasant, and restarting the system when people have left the room (using a remote control or a timer).
Notably, there are water- and oil-based underfloor heating systems that operate by passing electrically-heated water or oil through pipes laid under the floor. Heating of the water or oil can take place in one central location within the building where energy is supplied for heating the liquid to the appropriate temperature. As high-intensity electric and magnetic fields may form in the location of the system's electric component for heating the liquid (water or oil), it is recommended to identify this location and to avoid spending a long time in its vicinity. If domestic heating is distributed through permanent smaller heating devices in the home, it is recommended to avoid spending long periods of time near such devices and to keep a distance of at least several tens of centimeters from their electric component.
29.6.16
Is there any risk associated with metal detector checks?
Metal detectors are designed specifically to detect metal objects at close range. Metal detectors use magnetic fields of very low frequency and weak strength. These fields are within the non-ionizing part of the electromagnetic spectrum; low frequency radiation that cannot cause any change to the structure of materials through ionization (distancing an electron from an atom), as opposed to ionizing radiation (for example X-rays and gamma rays).
The operating mechanism of hand held metal detectors is based upon active detection – producing an alternating magnetic field at very low frequencies, by a coil, and detection of changes in the magnetic field close to the detector as a result of the presence of metallic objects, using a coil (usually a different coil is used for detection). When metallic objects are present, the alternating magnetic field acting on them causes electrical currents to flow in them and creates secondary magnetic fields that are detected by the metal detectors and trigger an alert.
The strength of the magnetic fields created by metal detectors is relatively low, so the exposure of people being checked to magnetic fields meets international standards.
Regarding health effects, the exposure to magnetic fields as a result of metal detector use is at a low level compared to permissible levels, and therefore there is no acute effect at these frequencies (neural or muscular excitation). Regarding long term effects, there is little information in the scientific literature about prolonged (“chronic”) effects of the intermediate frequency (IF) range, to which metal detectors belong. In addition, it should be noted that exposures are very brief during the scan and there is not extended exposure.
That said, it is generally accepted that people with cardiac pacemakers or other implanted medical devices should take care regarding use of metal detectors. Guidelines and regulations do not include any stricter limitations on magnetic field exposure for pregnant women than for others. There are countries and organizations that allow pregnant women to undergo separate checks.
12.3.2018
Does radiation from Wi-Fi network pass through walls?
Overall, radiation does penetrate walls, but this radiation is weakened as a function of the type of wall and the presence of openings such as doors etc. (namely the radiation measured on the other side of the wall and passing through it, will generally be up to tens of times weaker than that measured in the room where the router is located). This is also true for wireless routers and for cellphone radiation, which uses Wi-Fi or cellular networks.
In accordance with the precautionary principle, the most important rule for limiting exposure to non-ionizing radiation is to distance the radiation source from the body, since radiation drops significantly as the distance from the radiation source grows. Therefore, moving a wireless router to another room and using a cellphone in another room achieve the advantage of reducing the level of radiation relative to the adjacent room, both by increasing the distance and by the blockage created by the wall material.
The cumulative effect of these reductions usually leads to the radiation level in the adjacent room being thousands to hundreds of orders of magnitudes lower than in the room where the sources are located (the wireless router or cellphone).
What is the level of radiation exposure from using internet based television?
Television using a home Wi-Fi network, serves as a “consumer” of this network. Because the broadcasted information uses relatively big files (video files), it often causes the wireless router to operate at its maximal capacity. Nevertheless, it should be clarified that even under these circumstances, the level of radiation exposure from the router is relatively low. For example, at a distance of 1 meter from the wireless router operating at full capacity, the exposure level is about 1 microWatt per cm2. This level of exposure is 1/1000 of the maximal exposure level set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and about 1/100 of the recommended levels of prolonged exposure set by the Ministry of Environmental Protection. When the distance from the router is greater, the radiation level decreases with the distance squared (doubling of the distance leads to a 4 fold decrease in radiation level etc.)
