Other Frequently-Asked Questions
- Why ICNIRP guidelines set the reference value for the exposure limit for the general public to be five times as strict as that for the occupationally exposed population?
- The occupationally exposed population consists of adults who are generally exposed under known conditions and are trained to be aware of potential risk and take appropriate precautions. By contrast, the general public comprises individuals of all ages and varying health, and may include particularly susceptible groups or individuals. In many cases, the general public is unaware of their exposure to EMF, and cannot reasonably be expected to take precautions to minimize or avoid exposure. These considerations underlie the adoption of more stringent exposure restrictions for the general public than for the occupationally exposed population.
- Would you define the term "long-term effects" described in WHO Fact Sheet No. 322?
- Effects that instantly take place from exposure to very strong magnetic fields are called short-term effects. Effects other than short-term effects are collectively referred to as long-term effects.
- As the size of a transmission tower or line increases, does the magnetic field intensity also become stronger?
- A larger transmission tower usually has thicker conductors that more electric current can flow through, but larger transmission towers and lines also have conductors at an aerial location higher above the ground.
The intensity of a magnetic field generated from transmission lines is proportional to the electric current and roughly inversely proportionate to the square of the distance from the conductor (source of magnetic field). Hence, the distance from the source of a magnetic field is related to the intensity more closely than the value of the electric current. Therefore, the intensity of a magnetic field near the ground does not always depend on the size of the transmission tower and lines.
- Do all home electric appliances generate an electromagnetic field? Does the electromagnetic field remain after the home electric appliance is turned off?
- An electric field arises when voltage exists; a magnetic field arises where electric current flows. Therefore, an electric field arises when a home electric appliance is plugged in. Furthermore, a magnetic field arises when a home electric appliance is in use. An electromagnetic field collectively refers to an electric field and magnetic field. Therefore, when a home electric appliance is used, an electromagnetic field always arises.
- I would like to know about EMF measurements from home electric appliances.
- The EMF measurements of home electric appliance are described in a survey report (Fiscal 2007 Survey of Measurements of EMF Generating from Home Electric Appliances (10Hz to 400 kHz)) prepared by the Association of Electric Home Appliances, a foundation in Japan. For more information, visit their association website.
- Is it true that the more we use home electric appliances, the more we are exposed to EMF?
- Yes, the more we use home electric appliances, the more EMF arise. However, EMF decreases rapidly as the distance from the source increases.
- I would like to know the health effects of EMF generated from home electric appliances. Has any safe distance been set?
- No safe distance standard has been set. However, the intensities of magnetic fields generated from home electric appliances are well below the magnetic field exposure limits (200 μT for 50 Hz and 60 Hz) in the guideline of the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Furthermore, the intensity of a magnetic field is characterized as being proportional to the amplitude of the electric current and is inversely proportionate to the square of the distance from the generating source (that is, when the distance doubles, the intensity of the magnetic field becomes one-fourth). Therefore, even when you simultaneously use a number of home electric appliances in an ordinary living environment, the sum of their intensities are unlikely to exceed the magnetic field exposure limits of the ICNIRP guidelines.
If you are still anxious about magnetic fields, keep yourself away from any home electric appliances in use as well as the power supply cable so as to have lower exposure to the magnetic field.
- What is the difference between an IH stove and a radiant cooker?
- Their heating mechanisms are different. An IH stove uses induction heating and directly heats a pot with EMF at a frequency ranging from 20 to 90 kHz. Meanwhile, a radiant cooker heats the heating element (nichrome wire) in the cooker to transmit the heat to the pot.
- I have heard that study results on health effects from mobile phones will be released to the public. Do you know the time of release and the expected contents?
- At present, the International Agency for Research on Cancer (IARC), an affiliate of the WHO, has been leading an international epidemiological study (INTERPHONE study) based on research data obtained from 13 countries including Japan to conduct analysis and assessment on the relationship between the use of mobile phones and cancer.
After completing this analysis and assessment, the WHO will assess all health risks of exposure to high-frequency EMF (radio waves). The final assessment report will be disclosed to the public around 2013.
- My neighbour uses a wireless LAN in the house. Are there any health effects from the LAN?
- WHO Fact Sheet No. 304 (Base stations and wireless technologies) estimates LAN as follows: "Considering the very low exposure levels and research results collected to date, there is no convincing scientific evidence that the weak RF signals from base stations and wireless networks cause adverse health effects."
Japan regulates all equipment generating radio waves under the Radio Law. Wireless LANs are also subject to the "Radio Wave Protection Guidelines" so that their intensity does not exceed the reference value.
☆ Rules of Using Radio Waves, Radio Wave Usage website, Ministry of Public Management, Home Affairs, Posts and Telecommunications
- Would you name the regulations that control mobile phones, their base stations, and wireless LANs?
- Mobile phones are controlled by the "SAR Regulations on Mobile Terminals within Wireless Facilities Regulations," while mobile phone base stations are controlled by the "Wireless Base Station Regulations within the Enforcement Regulations of the Radio Law." Likewise, wireless LANs are controlled on their transmitting side and receiving side.
SAR (specific absorption rate) has been adopted as a method of assessing thermal effect when exposed to 100 kHz or greater frequencies (radio waves). SAR is classified into "whole-body average SAR" and "local SAR."
The reference values are set after the safety rate involving effective levels of thermal action is considered. Specifically, the whole-body average SAR is set at 0.08 W/kg for mobile phone base stations and the local SAR is set at 2W/kg (on average for 6 minutes) for mobile phones used near the head.
- I would like to know the intensity of EMF (radio frequency) generated from base stations for mobile phones. Could you measure EMF for us, or would you lend such a measurement instrument?
- The Japan EMF Information Center (JEIC) neither offers the service of measuring EMF at mobile phone base stations (radio frequency) nor lends such a measurement instrument.
- I plan to build a solar power generation system on the roof of my house. Will the system have EMF health effects?
- A solar power generation system consists of solar panels, a power conditioner, and a distribution board. The solar panels generate direct current electricity. The power conditioner converts the direct current into alternative current for commercial frequencies used in general houses (50 or 60 Hz) and connects it to the distribution board.
When solar panels generate direct current electricity, a static electric field and a static magnetic field arise in the surroundings. The WHO publicizes Environmental Health Criteria No. 232 (Static electric and magnetic fields) and Fact Sheet No. 299 (Static electric and magnetic fields) on the health effects of static electric fields and static magnetic fields.
Meanwhile, a power conditioner converts direct current electricity into alternative current electricity. It is the same type of electrical apparatus as the general inverter (converter of alternative current into direct current) used for lighting fixtures and air conditioners. Therefore, the health effects of EMF generated from power conditioners are regarded as being of the same degree of EMF generated from home electric appliances.
- Will hybrid cars and electric cars generate EMF? If so, what intensities of magnetic field do they have?
- Both hybrid cars (gasoline engine + battery, and motor) and electric cars generate EMF because they use electricity. Assessments of exposure to magnetic fields of hybrid cars and electric cars were reported at the BioEM 2009 Meeting held in June 2009 (jointly hosted by the European BioElectromagnetics Association (EBEA) and the Bioelectromagentics Society (BEMS)). The result of measuring EMF of direct current to 100-Hz frequencies leads to the conclusion that "the average exposure was within 5% of the reference level for the public specified in the ICNIRP guidelines(1998) and the maximum value was up to about 15% of the reference level."
- What is electromagnetic (wave) hypersensitivity (EHS)?
- WHO Fact Sheet No. 296 (Electromagnetic hypersensitivity) reports that "the symptoms most commonly experienced include dermatological symptoms (redness, tingling, and burning sensations) as well as neurasthenic and vegetative symptoms (fatigue, tiredness, concentration difficulties, dizziness, nausea, heart palpitations, and digestive disturbances)." Some people allege that such symptoms are related to EMF exposure.
Double-blind studies were conducted to confirm whether EHS individuals can recognize symptoms or detect EMF exposure when they were exposed or not exposed to EMF without seeming to do so. These studies have shown that symptoms are not correlated with EMF exposure.
The same WHO fact sheet has suggested that symptoms might arise from environmental factors unrelated to EMF including stress in the workplace or living environment, as well as stress reactions as a result of worrying about EMF health effects.
- I may have electromagnetic hypersensitivity (EHS). Can a hospital diagnose my condition? What hospital department should I visit?
- EHS is not an official diagnostic name. It is just a name used in the vernacular. In addition, since EHS has not been proved scientifically to be caused by EMF, no correct diagnosis can be expected. Because of these factors, it is difficult to address EHS at present. Thus, unfortunately, no recommendable diagnostic department is available at hospitals. However, people who feel under psychological stress could visit the internal medicine department or psychosomatic medicine department of a hospital for therapy.
- Are there any concrete measures to protect ourselves from EMF?
- There are a number of possible physical measures to protect you from EMF. However, since these measures are very costly, they are not practical. EMF has different properties depending on the frequency. From the standpoint of preventing EMF, EMF could be classified into low-frequency EMF of up to about 100 kHz and high-frequency EMF of 100 kHz or above.
Electromagnetic waves propagate when an electric field and magnetic field induce each other into radio waves. Therefore, when you prevent an electric field or magnetic field, the radio waves will no longer spread forth (but you will not be able to listen the radio). If an EMF source is enclosed with electrically conductive material and earthed, a shielding effect is possible.
Meanwhile, for low frequency, the electric field must be treated differently from the magnetic field. To prevent a magnetic field, high-permeability material (alloys such as electromagnetic pure iron or permalloy that transmits magnetic force lines) can be used. An electric field can be treated in the same way as a high-frequency field. In either case, however, if the EMF source is not enclosed completely, the magnetic field is transmitted or EMF wraps around the source, this might be resulting in inadequate shielding effect.
- EMF protection products (EMF protection aprons, curtains, ferrite sheets for mobile phones, etc.) are sold on Internet websites. Are these effective?
- We cannot answer regarding their effectiveness correctly because we do not have their data. In general, however, it seems that products that can effectively shield a low-frequency magnetic field are hardly available.
- My PC screen flickers when a train passes nearby. Why does this happen?
- When a train passes, EMF generated from feeder cable and train may have an effect on a display device (cathode-ray tube TV and PC) that draws images by electronic beams, causing screen flickers. This happens because beams are disturbed by the external magnetic field, causing image dislocations in the screen.
- I have had an artificial pacemaker implanted recently. Can I have an MRI for diagnosis? Are there any points of caution?
- A medical instrument, such as an MRI, that generates a strong magnetic field may cause an artificial pacemaker to malfunction. It is recommended that you consult a doctor when you visit a medical institution.
- Will radio waves from mobile phones cause an artificial pacemaker to malfunction? What about IH stoves and airport gates?
- Past experiments have confirmed that some artificial pacemakers malfunctioned when a mobile phone approached the pacemaker within a certain distance (about 15 cm). For details, visit the website of the Ministry of Internal Affairs and Communications to read "Results of Studying Effects on Medical Instruments from Radio Waves" and the website of the Electromagnetic Compatibility Conference Japan to read the "Guidelines for Using Mobile Phone Terminals to Prevent Radio Wave Effects on Medical Instruments."
Concerning IH stoves, carefully read and follow the caution instructions in their manuals. If you have an artificial pacemaker, tell the airport officials when you pass the gate.
- A nearby house emits an electromagnetic wave in the direction of my house. I also hear some scary sounds. I want to know the cause, so I can feel safe. How can I do this?
- An electromagnetic field is measurable. Ask a research institution to locate the source and type of electromagnetic field and measure the field. This investigation may identify the cause.
An electromagnetic field itself generates no sound. To generate an electromagnetic field for the purpose to carry out an attack on a certain person is very difficult technically and economically. Consider causes other than EMF. It may lead to finding a solution.
- Would you explain thinking intervention? Can current technology do it?
- It is known that some typical biomagnetic technology covers fMRI (functional magnetic resonance imaging) that visualizes cerebral neurobehavior through changes in blood magnetism stemming from cerebral blood flow change, as well as technology applied to medical treatment using TMS (transcranial magnetic stimulation).
However, if you think that thinking intervention is "technology that can input external information into the mind of another person without contact (for example, radiating an electromagnetic field)" as if the person is thinking it by him or herself, we cannot confirm the existence of such technology.
- Would you explain thinking tapping? My thinking is being tapped.
- From brain waves, we can read electric potential-related internal and external events. In other words, a technique is available in which brain electric/magnetic signals are detected from electrodes put on the scalp. When such signals are related with electric potential patterns, which are generated from our thinking and behaviour, we can measure this thinking and behaviour.
However, if "thinking tapping" is assumed to be a "technique that can read thinking externally without contact (for example, radiating electromagnetic waves)," we cannot confirm the existence such a technique.
- Is there any good use of electromagnetic fields for the human body, such as therapy equipment?
- There are many kinds of electromagnetic therapy equipment. Among quasi-pharmaceutical products specified in the Pharmaceutical Affairs Act, some equipment uses electromagnetic waves to improve circulation in the body. In clinical practice, there is diathermy thermotherapy intended for treatment of cancer and improvement of functions of joints. This therapy is to utilize the thermal action of strong electromagnetic waves with the frequency of 10 megahertz (MHz) or more to the human body.
- I would like to know about the current state of cohort studies (epidemiological studies).
- There are several study methods for epidemiological studies, such as synchronic studies, case control studies and cohort studies. The Cohort study is to follow up a group (cohort), directly measure morbidity, an indicator for likeliness of developing the disease, and assess the impact of risk factors. It has higher accuracy compared to other epidemiological study methods. However, a large number of people need to be surveyed in order to study diseases that have small number of affected patients, e.g. three patients per 100 thousand people like childhood leukemia. To conduct the study actually, there are many issues including cost.
- I would like to know the difference between connection and causal relationship.
- Connection means that there is a connection between a factor and a result. In case that a cause and mechanism are proved for why a factor caused a result, it is called causal relationship.
- I would like to know about hearing impairment caused by ultrasound.
- Ultrasound is a high-frequency sound wave that human hardly hears. It is different from electromagnetic fields. When the frequency exceeds 10 kilohertz (kHz), we gradually have a trouble hearing the sound. It is said that we can hardly hear it in general, when it exceeds 16 to 18 kilohertz (kHz). One of the types of hearing impairment is noise deafness. If you often use an ultrasonic washing machine in working environment, you need to put on soundproof ear muffs.
- Does the food cooked by a microwave oven have any effect on our health?
- As World Health Organization (WHO) Information Sheet “Microwave oven” states “the food cooked by a microwave oven is as safe as those cooked by a conventional oven and have the similar nutrition values,” the components of food cooked by a microwave oven do not have any adverse effect on health.
⇒ Reference material
☆ WHO Information Sheet “Microwave Oven” (Japanese translation) PDF file download
- When the steel tower was constructed, no explanation was made to the residents. Don’t we have any other option but to leave as it is?
- In general terms, as WHO guidance of Fact Sheet No.322 states that “the promotion of coordination and discussion with business sectors, local government and citizens may be included in the planning process of facilities that generate extremely-low frequency electromagnetic fields,” we think communication among stakeholders is very important.
⇒ Reference material
☆ Fact Sheet No.322 “Exposure to extremely low frequency fields” (Japanese translation) PDF file download
- In Japan, what research institutions investigate health effects of electromagnetic fields in Japan?
- In the past, the National Institute of Public Health (former Institute of Public Health) and the National Institute for Environmental Studies conducted the research about low-frequency electromagnetic fields, but currently they don’t.
Research institutions for high-frequency electromagnetic fields include the National Institute of Public Health (former Institute of Public Health) and the National Institute of Information and Communications Technology (NICT). Research of low and high frequency electromagnetic fields is carried out at multiple universities in Japan.