It has been much discussion at TreeHugger about the danger of Electromagnetic Fields (EMF) generated by cellphones, routers, power lines and microwave ovens. Some people think it is a serious issue; WIFI is banned at Lakehead University, and inScandinavia there are cellphone-free beaches for people with electro-hypersensitivity. Clarins even makes a spray to protect your skin from it. Other people feel that it is not a problem.

Treehugger Labs wanted to determine this once and for all, and has spent the past year studying the issue. We wanted to pick a life form that would not move around a lot so that we could ensure that there were no other factors, and we are, of course, against animal testing, so we chose trees as our subject. We searched for trees that grew near power lines to see what the effect of the EMF was on the form of the tree.

We were surprised to find that maple trees growing up under power lines were profoundly influenced by the lines. They tended to develop a bifurcated “Y” formation as the limbs seemed to grow away from the lines themselves. We call this effect “electrobonsai” because it looks like it might have been shaped by humans.

In tree after tree, we saw the electrobonsai effect. The limbs clearly are trying to move away from the power lines. They appear healthy and have been around for a long time, but definitely try to keep a safe distance away from the EMF.

The wires are rated at 22 KV, 60 Cycle. Most of the city was rewired from 4Kv over the last few years so it appears that there is no relationship between the voltage and the electrobonsai effect.

As you can see from our control group, normal maple trees do not take the bifurcated Y shape but branch randomly.

The team concluded that there is no question, tree limbs are distorted by the power lines, and the only thing that could be emanating from the lines is the EMF. Sometimes we have seen that where they could not grow away from the lines, limbs are sheared off as if by a chainsaw, and then exude a brown protective coating to seal the wound. Who knew that plants could develop such sophisticated mechanisms for dealing with EMF.

Judging from the average distance of limbs from power lines,(2.4 metres or 8 feet) we have concluded that it is probably prudent to keep transformers, routers, cell phones and hair dryers eight feet from your head at all times.

Did you know that your clock, mp3 player, computer, hair dryer, television, cellphone or cordless phone could be frying your brain. Tissue heating effects on a fifteen minute cellphone conversation that were viewed through thermograph show significant and dangerous levels of heat radiation. [...]

EMF meters are relatively cheap and you can buy them on ebay or other websites for as little as thirty bucks. This device is used to measure electromagnetic fields hence the name EMF meter. One of the simpliest to use is called the Gauss Master, it is rectangular in shape and very simple, the only [...]

Radiation travels at the speed of light and vibrates in waves. The electromagnetic spectrum is used to classify this wide range of electromagnetic waves and uses their wavelengths and frequencies to differentiate themselves. Although this spectrum is continuous it has been divided into seven categories for easier identification. These are radio, microwave, infrared, visible, ultraviolet, [...]

Could using your cellphone a lot during pregnancy affect your baby’s health? A recent study released in Denmark that followed thirteen thousand children from infancy to the age of seven had the following results. Researchers found that mothers who used their cellphone two to three times a day during pregnancy increased the risk of their [...]

An electromagnetic field detector is used to detect sources of electromagnetic radiation and to evaluate their security levels. In other words this device allows you to find out electromagnetic fields and to determine the level of their intensity. One of the most popular emf detectors is called the Gaussmeter. The sources of can high voltage [...]

Electric vehicles took the country by storm this week as both the Nissan Leaf and the Chevy Volt were officially released to eager customers – if you're still trying to decide between the two, check out our electric vehicle smackdown, which compares the two EVs based on their most important features. We also took a spin inside Honda's ele……

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At a distance of about 300 ft. at times of average electricity demand, the magnetic field from many lines can be similar to typical background EMF levels found in most homes. The distance at which the magnetic field from the line becomes indistinguishable from typical background EMFs differs for different types of lines. Neighborhood distribution lines can also sometimes produce significant magnetic fields, depending on the amount of current they carry.

Q. How strong are the EMFs from electric power substations?

A. In general, the strongest EMFs around the outside of a substation come from the power lines entering and leaving the station. The strength of the EMFs from transformers decreases rapidly with increasing distance. Beyond the substation fence, the EMFs produced by the equipment within the station are typically indistinguishable from background levels.

Q. What typical EMF sources do I encounter when traveling?

A. Inside a car or bus, the main sources of 60-Hz magnetic field exposure are those you pass by (or under) as you drive, such as power lines. Car batteries involve DC rather than AC. Alternators can create EMFs, but not at 60 Hz.

Most trains are diesel-powered. Some electrically powered trains operate on AC, such as the Baltimore-Washington commuter train. Measurements taken on this train in 1991* showed 25-Hz magnetic field strengths as high as 500 mG in the passenger areas at seat height. Other trains, such as the Washington D.C. Metro and the San Francisco Bay Area Rapid Transit, run on DC, but even these trains are not free of AC fields. Areas of strong AC magnetic fields have been measured on the Washington Metro close to the floor, presumably near equipment located underneath some subway cars. Train motors and other equipment can create alternating fields at higher than 60-Hz frequencies. In addition to sources of magnetic field exposure from the train itself, train passengers are exposed to magnetic fields from sources the train passes on its route.

Q. Is there something significant about the 2-mG magnetic field level?

A. A typical American home has a background magnetic field level (away from any appliances) that ranges from 0.5 mG to 4 mG, with an average value of 0.9 mG.* Most ordinary electrical appliances produce higher localized magnetic fields.

Several EMF epidemiological studies have used 2 or 3 mG as a cutoff point to define broad categories of exposure. Below this level, subjects are considered “unexposed,” and above this level they are considered “exposed.” In some studies, a higher cancer risk was found within the exposed group. Other studies found no such increased risk. The significance of 2 mG is as a boundary to define the exposed group in some studies, not as a safety threshold. Although some experiments with cells have reported effects at field levels as low as 2 mG, there is no laboratory evidence for adverse human health effects at this level.

The Swedish study (discussed under Human Health Studies) suggested a dose/response relationship for EMF exposure: The higher the estimated magnetic field exposure, the higher the cancer risk. To deduce from the Swedish study, however, that 2 mG is some sort of safety threshold is to read far too much into the data. The Swedish government has so far concluded that current knowledge does not provide sufficient basis for setting exposure limits (see Government Actions).

*This estimate is based on the EPRI study of 992 homes. An average magnetic field measurement was calculated for each home, based on measurements conducted in each room. The average of the 992 individual “home averages” was 0.9 mG.

Q. How can I find out how strong the EMFs are where I live or work?

A. For specific information about EMFs from a particular power line, contact the utility that operates the line. Most utilities will conduct EMF measurements for customers at no charge. You can make your own field measurements if you have a gaussmeter, available from several companies. Independent measurement technicians will conduct EMF measurements for a fee. In some cities, they are listed in the yellow pages of the telephone book under the heading “Engineers, environmental.” Gaussmeters can be easily purchased for personal use.

Q. How does the magnetic field throughout my home compare with that of other homes?

A. As a source of comparison with the magnetic field throughout your home, see the figure below.

(The EPRI study of 992 homes was not designed to measure people’s actual exposure to magnetic fields. Instead, it focused on identifying internal and external sources of these fields in the home. Your exposure to magnetic fields depends on how much time you spend near various sources and on the strength of the fields produced by the source)

This chart summarizes data from a study by the Electric Power Research Institute (EPRI) in which spot measurements of magnetic fields were made in the center of rooms in 992 homes throughout the United States. Half of the homes studied had magnetic field measurements of 0.6 mG or less, when the average of measurements from all the rooms in the home was calculated (the all-room mean magnetic field). The all-room mean magnetic field for all homes studied was 0.9mG. Only 15% of the homes had mean magnetic fields greater than 2.1 mG. The measurements were made away from electrical appliances and primarily reflect the fields from outside power lines, household wiring, and electrical grounding sources.

Q. Is it safe to live close to a transmission line?

A. Living close to a transmission line can increase your overall exposure to EMFs. As discussed earlier, despite research findings to the contrary, government health or safety organizations worldwide have reportedly refused to conclude that EMFs cause cancer or other health effects.

It is generally acknowledged that several studies have reported increased cancer risks, especially for children living close to high-current power lines. Although these studies suggest potential risks, scientists do not yet know whether EMFs, other factors, or methodological problems are responsible for their findings.

It is possible that future studies will provide sufficient information to establish whether EMFs are a hazard to human health. The newer studies may also show that factors other than EMFs were responsible for effects reported in earlier studies. It is also possible that, even with more research, there will be no scientific resolution to the EMF issue in the near future.

The answer to this question, therefore, involves (1) a great deal of judgment about the meaning of existing scientific evidence, (2) speculation about the possible results of future studies, and (3) individual perceptions about the relative importance of various potential health risks.

During this period of uncertainty, there are some things that you can do to help answer this question.

1. Follow the EMF issue by reading various sources and talking with people who are working to resolve the issue. The EMF RAPID Program in cooperation with the U.S. Environmental Protection Agency, provides a toll-free public information telephone line to answer EMF-related questions and direct callers to further sources of information.
   The EMF “Infoline” number is 1-800-363-2383. (In Washington D.C., call 484-1803.)
2. Find out about the EMF levels produced by the particular source that concerns you. If the source is a power line, you may be far enough away that EMF levels are negligible.

Q. What can be done to limit EMF exposures?

A. There are a number of ways to reduce exposures to EMFs. Some are as easy as standing back from an appliance when it is in use. Remember that magnetic fields from appliances drop off dramatically in strength with increased distance from the source.

Other EMF reduction steps, such as correcting a household wiring problem, are worth doing anyway for safety reasons. But what about more costly actions, such as burying power lines or moving out of a home? Because scientists are still debating whether EMFs are a hazard to health, it is not clear how much should be done at this time to reduce exposures. Some EMF reduction measures may create other problems. For instance, compacting power lines to reduce EMFs can increase the danger of accidental electrocution for line workers.

A concerted effort to provide scientifically valid research on which to base decisions about EMF exposures is under way, and results are expected in the next several years. Meanwhile, some authorities recommend taking simple precautionary steps, such as the following:

• Increase the distance between yourself and the EMF source-sit at arm’s length from your computer terminal.
• Avoid unnecessary proximity to high EMF sources-don’t let children play directly under power lines or on top of power transformers for underground lines.
• Reduce time spent in the field-turn off your computer monitor and other electrical appliances when you aren’t using them.

Q. Are products advertised as having reduced magnetic fields legitimate?

A. This question must be answered appliance by appliance, depending on the claims of the manufacturer. According to the U.S. Food and Drug Administration’s Center for Devices and Radiological Health, “low magnetic field” electric blankets do produce significantly lower magnetic fields than older versions because of wiring redesign. It is advisable, however, to be cautious about product claims that sound too good to be true, given the complexity of the EMF issue.

Q. What have governmental reviews concluded about EMFs and cancer?

A. Most recent reviews have concluded that the existing evidence, although suggestive, is not sufficient to show that EMFs cause cancer. These include national reviews by the U.S. Environmental Protection Agency, the Committee on Interagency Radiation Research and Policy Coordination, the Australian Minister of Health, the National Radiological Protection Board of the United Kingdom, the Danish Ministry of Health, the French National Institute of Health and Medical Research, and reviews sponsored by the states of California, Texas, Connecticut, Illinois, Maryland, and Colorado.

The Swedish government issued a public information document in May 1994 that states, “We suspect that magnetic fields may pose certain risks to health, but we cannot be certain.” While research is under way to pin this down, the report continues, “there is good reason to exercise a certain amount of caution.” The Swedish government recommends against locating new homes and schools near existing electricity generating plants and proposes that high magnetic fields in homes, schools, and workplaces be limited. It specifically states, however, that “current knowledge is not sufficient for us to tell how magnetic fields affect us. So we do not have a basis on which to set [exposure] limits.”

In nearby Denmark, a government agency concluded there was no scientific reason to establish magnetic field standards for high-current lines

Q. What effects of EMFs have been reported in laboratory studies?

Laboratory studies to date have not answered questions about possible human health effects. These studies are, however, providing clues about how EMFs interact with basic biological processes. The cell membrane may be an important site of interaction with induced currents from EMFs.

Keep in mind that some of these effects are within the “normal” range of variation. A biological response to a particular stimulus does not necessarily result in a negative health effect.

Q. What about effects of EMFs on the hormone melatonin?

A. Melatonin is a hormone produced mainly at night by the pineal, a small gland in the brain. One reason scientists are interested in melatonin is that it could help explain results of some EMF epidemiological studies. Melatonin has been reported to slow the growth of some cancer cells, including breast cancer cells, in laboratory experiments. If power frequency EMF can affect melatonin in humans, this could be a mechanism to explain results of some EMF studies of breast cancer.

In the 1980s, scientists found that in rats exposed to 60-Hz electric fields, nighttime melatonin levels were reduced. Other studies have since reported that both AC and DC magnetic fields can also affect melatonin levels in rats and hamsters. These experiments are very delicate and depend on a combination of factors such as age of the animals and length of day. Melatonin levels were not affected in sheep raised for nearly a year in the EMFs directly beneath a 500-kV transmission line. Experiments with baboons also showed no changes in melatonin. The Midwest Research Institute (MRI) has studied the effect of 60-Hz magnetic field exposure on human melatonin. In 1993 MRI reported that although subjects showed no effect on the average, those individuals with naturally lower levels of melatonin did show a small further decrease. However, in 1994 MRI reported that a second study, specifically designed to replicate the earlier results, found no such effect.