- Does the government implement any regulations on EMFs generated from power facilities?
- High voltage transmission lines are regulated by a technical standard in which the electric field of electric facilities is required to remain within 3 kV/m. However, this regulation is not to protect people's health from EMF effects but to protect people from electric shocks.
Power facilities (including high voltage transmission lines, distribution lines, transformers and substations) are regulated by a technical standard in which the magnetic field of electric facilities is required to remain below 200 microtesla (μT).(a technical standard (電気設備に関する技術基準を定める省令) was established by an Ordinance of the Ministry of Economy, Trade and Industry)
- Are there any EMFs (radio wave) limits on IH stoves and microwave ovens implemented by the government?
- The intensity of EMF that IH stoves generate is stipulated in the Enforcement Regulations of the Radio Law, as stated below:
Article 46-7 Paragraph 2 (3), Enforcement Regulations of the Radio Law:
The intensity of a leaking electric field shall be one of the following values or under at a 30 m distance from the oscillator of the facility in question.
(1) 1(m/mV) in the use of frequency
(2) 30(μV/m) within frequencies of 526.5 to 1,606.5 kHz.
(3) √(20P)(μV/m) for frequencies other than the frequencies listed in items 1 and 2 above.
(P is wattage of high frequency output. High frequency output under 500 watts should be set to 500, while outputs that exceed 2,000 watts should be 2,000 watts.)
The intensity of EMF (microwaves) generated from microwave ovens is stipulated in the Electrical Appliance and Material Safety Law and the Enforcement Regulations of the Radio Law as follows:
Schedule 8-2 (95) G, Power Density of Radio Wave Leakage Outside the Microwave Oven*, Ministerial Ordinance concerning Technical Standards for Electrical Appliances, Electrical Appliance and Material Safety Law:
1(mW/cm2) or under at all points 5 cm distant from the surface of a working microwave oven with the door closed and 5(mW/cm2) or under when the working microwave oven ceases just before the door is opened
5(mW/cm2) or under after a durability test of electric current density of radio wave leakage conducted in accordance with the Enforcement Regulations of the Radio Law
* power density, power flux density: Radiation capacity (amount of energy of radio wave) per unit area vertical in the direction of radio wave propagation
- Are there any EMFs (radio wave) limits for home electric appliances other than IH stoves and microwave ovens?
- The only home electric appliances regulated in Japan for EMF are IH stoves and microwave ovens.
PCs and other electronic and electrical equipment also generate disturbance waves (electromagnetic waves) over a broad range of frequencies. Depending on the disturbance wave level, the waves may interfere with radio and TV reception, which is electromagnetic interference. To prevent such electromagnetic interference with electronic and electrical equipment, technical guidelines have been instituted voluntarily by the Voluntary Control Council for Interference by Information Technology Equipment (VCCI). Approximately 1300 companies belong to VCCI in Japan and overseas. When a manufacturer belonging to VCCI ships electronic or electric equipment to a buyer in Japan, the manufacturer is required to comply with the electromagnetic control measures pursuant to the guidelines to deter disturbance waves and prevent interference.
However, VCCI's voluntary guidelines do not cover home electric appliances regulated in the Electrical Appliance and Material Safety Law and wireless equipment regulated in the Radio Law and regulations. Such appliances and equipment are only subject to the Electrical Appliance and Material Safety Law and the Radio Law and regulations.
- Do any countries abroad regulate EMFs generating from power facilities?
- Many countries abroad, mainly in Europe have introduced regulations or guidelines pursuant to the exposure limits specified by the International Commission on Non-Ionizing Radiation Protection (ICNIRP).
In addition to the exposure limits suggested in the ICNIRP guidelines, Switzerland and Italy have established emission limits for magnetic fields at the locations such as houses, hospitals, and schools, which especially need protection based on a precautionary policy.
- Does Sweden have very strict EMF control?
- Sweden has recommended values of electric and magnetic fields pursuant to the ICNIRP guidelines but no regulations.
Sweden is reputed to have decided to control the magnetic fields generating from transmission lines to keep power lines apart from schools. We have not yet been able to confirm that Sweden controls magnetic fields generated from power lines or that Sweden has ordered power lines to be kept apart from schools.
- If the risk of childhood leukaemia incidence doubles with 0.4 μT or more, should the planned limit value be less than 0.4 μT?
- The WHO concludes that the relationship between long-term exposure to EMF in the living environment and the increase in childhood leukaemia is too weak to be regarded as causal. In addition, even if there is a causal relation between EMF exposure and childhood leukaemia, the WHO also states the effects on public health are minor. Based on these points, the WHO has indicated against adopting 0.4 μT, which is indicated in epidemiological studies, as the limit.
- I have heard that there is no house under transmission lines in America. Is it because electromagnetic fields are dangerous?
- There is a concept of access right in America. Electric power is transmitted from power stations. The transmission route is regarded as a road that carries public electricity. Therefore, electricity companies buy land under transmission lines. It is not because electromagnetic fields have adverse effects on health. It is because of the difference in land area between America and Japan. From a viewpoint of useful use of land, there may be a house under transmission line in Japan.
- Why do the limit values for exposure to magnetic fields provided in the former ICNIRP guidelines (1998) vary by frequency? (100μT at 50Hz and 83μT at 60Hz)
- In the low-frequency range including 50Hz and 60Hz, what you should prevent is the adverse effect caused by current induced into your body. It is suggested that the size of current induced into human body as a result of exposure to electromagnetic fields of 4Hz to 1kHz should be limited to 2mA/m2 regularly for general public. However, it is extremely difficult to check whether the current induced into the body exceeded 2mA/m2 or not when you are exposed to external magnetic fields. Therefore, the external magnetic field that is necessary to induce the current of 2mA/m2 into the body is used as an alternative indicator. The relation between the external magnetic fields and the induced current is expressed by relatively simple equation. According to Faraday’s law of electromagnetic induction, the electric conductivity of a disk with the diameter of r is constantly σ. If time-varying electromagnetic fields “B” (magnetic flux density) with frequency of “f” interlink vertically with the disc, the induced current density “J” that flows along the most outer perimeter of disc is expressed by the following equation.
Taking the disc as a cross-sectional model of human body, if the size of the magnetic field “B” to which the body is exposed is constant, the current density induced into the body is proportional to frequency “f”. On the contrary, in order to keep the induced current in the body constant at 2mA/m2, the external magnetic field should be replaced by the size inversely proportional to frequency. This is the reason why the limit value for exposure to magnetic fields is different between 50Hz and 60Hz.
- The reference levels for general public in the ICNIRP guidelines released in 1998 were revised in November 2010. The levels were relaxed from 100μT (for 50Hz) and 83μT (for 60Hz) to 200μT (for 50Hz and 60Hz). I would like to know the reason for the revision.
- The new guidelines of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) show the following rationales: current induced inside a human body was adopted as the indicator for the base limit: great importance was attached to magnetic flash phenomenon as a basis of the base limit: the calculation method used to derive current induced inside a human body and the reference level was improved tremendously, and: the use of long-term effect of exposure to low-level magnetic fields is insufficient for the basis for exposure limit. As a result, the reference levels of magnetic fields for 50Hz and 60Hz were changed to 200μT in the new guidelines.
- What is the reason for the difference in contents between WHO Environmental Health Criteria (EHC) No.238 “Extremely Low Frequency Fields“ and Fact Sheet No.322 “Electromagnetic fields and public health: Exposure to extremely low frequency fields “?
- Environmental Health Criteria (EHC) is the health risk evaluation document created by the task meeting that is consisted of experts selected by World Health Organization (WHO).
On the other hand, Fact Sheet is the official document of WHO. Approval by the Director-General is required for publication. Fact Sheet No.322 was publicized based on EHC No.238 to present what WHO thought about EHC No.238. The concept of risk management is basically the same between EHC No.238 and Fact Sheet No.322. Both of them cite the low-cost mitigation (reduction in magnetic fields) for newly established power facilities and products as an option of precaution measures against impact of long-term exposure. At the end of 2006 following the task meeting (held in 2005), however, WHO cancelled a submission of “Precaution framework.” As such, the expression of mitigation (reduction in magnetic fields) policy in EHC and that in the Fact Sheet is different. Additionally, the term “Precaution” is not used in the Fact Sheet, either.
- What is the difference between occupational exposure and exposure of general public used in international guidelines?
- Occupational exposure is the exposure of workers in working environment.
On the other hand, exposure of general public is the exposure of ordinary people. Ordinary people include people of all ages and various health conditions. As they are often not aware of their exposure, the limit for exposure is as five times as stringent for ordinary people than workers.
- What is the positioning of WHO information sheet?
- When the approval of Director-General of World Health Organization (WHO) is not obtained and it cannot be issued as a fact sheet, an information sheet is released with the approval by Cluster head. WHO decided not to release information sheet any longer in 2009. Since then, the information sheets have not been posted on the WHO website.
- Is WHO a reliable organization?
- Any risk evaluation cannot be free from uncertainty. There can be no perfect certainty in science. However, researchers around the world have made efforts to achieve nearly 100% certainty. The views of World Health Organization (WHO) can be interpreted as the aggregated views of such researchers.
- How are members of WHO task meeting selected?
- Members are selected from experts around the world in view of expertise, gender and regional balance. Those who have interest in electromagnetic field business are not selected. Staff of secretariat of World Health Organization (WHO) nominates members and a head of Cluster approves them. The Cluster is an organization placed under Director-General. There are nine Clusters in WHO.
- The use of electronic devices is restricted during take-off and landing of airplane. On what grounds is the restriction based on?
- Electromagnetic waves (electric waves) emitted from electronic devices have the potential to cause effect on electronic equipment and devices of the aircrafts. “Electronic devices that may pose a problem for safe operation of aircrafts” are defined in the Public Notice of the Ministry of Land, Infrastructure, Transport and Tourism.
- We are no longer asked to keep our cell-phones turned off at hospitals. I would like to know the reason for that. I would also like to know the rule for using cell-phones inside the hospital.
- There are various electronic devices in the hospital, and accurate medical devices may malfunction affected by electromagnetic waves (electric waves). In the past, use of high-power cellular phones was generally prohibited. However, with the progress of cellular phone technology, waves emitted from in-use cellular phones have become weaker. Therefore, we can use them inside the hospital except for operating rooms.