Excerpt from the World Health Organisations guidelines on ELF. Full link at

http://www.who.int/mediacentre/fact...index.html

As the WHO suggests the link is dubious and inconclusive at best.. In order to expose yourself to potentially high levels of electromagnetic feilds that can cause yourself problems you'd need to be sitting on top of the windmill for weeks. even then its probably not enough. 100uT is a very strong feild!!

I'd strongly suggest to all, that before making judgement calls on this so called 'health risk' that you take the time to read this, and all the other papers put together by non-biased scientists from all around world, who most likely can't spell pauatahanui, let alone even know where it is.




Electromagnetic fields and public health
Exposure to extremely low frequency fields

The use of electricity has become an integral part of everyday life. Whenever electricity flows, both electric and magnetic fields exist close to the lines that carry electricity, and close to appliances. Since the late 1970s, questions have been raised whether exposure to these extremely low frequency (ELF) electric and magnetic fields (EMF) produces adverse health consequences. Since then, much research has been done, successfully resolving important issues and narrowing the focus of future research.

In 1996, the World Health Organization (WHO) established the International Electromagnetic Fields Project to investigate potential health risks associated with technologies emitting EMF. A WHO Task Group recently concluded a review of the health implications of ELF fields (WHO, 2007).

This Fact Sheet is based on the findings of that Task Group and updates recent reviews on the health effects of ELF EMF published in 2002 by the International Agency for Research on Cancer (IARC), established under the auspices of WHO, and by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) in 2003.
ELF field sources and residential exposures

Electric and magnetic fields exist wherever electric current flows - in power lines and cables, residential wiring and electrical appliances. Electric fields arise from electric charges, are measured in volts per metre (V/m) and are shielded by common materials, such as wood and metal. Magnetic fields arise from the motion of electric charges (i.e. a current), are expressed in tesla (T), or more commonly in millitesla (mT) or microtesla (µT). In some countries another unit called the gauss, (G), is commonly used (10,000 G = 1 T). These fields are not shielded by most common materials, and pass easily through them. Both types of fields are strongest close to the source and diminish with distance.

Most electric power operates at a frequency of 50 or 60 cycles per second, or hertz (Hz). Close to certain appliances, the magnetic field values can be of the order of a few hundred microtesla. Underneath power lines, magnetic fields can be about 20 µT and electric fields can be several thousand volts per metre. However, average residential power-frequency magnetic fields in homes are much lower - about 0.07 µT in Europe and 0.11 µT in North America. Mean values of the electric field in the home are up to several tens of volts per metre.
Task group evaluation

In October 2005, WHO convened a Task Group of scientific experts to assess any risks to health that might exist from exposure to ELF electric and magnetic fields in the frequency range >0 to 100,000 Hz (100 kHz). While IARC examined the evidence regarding cancer in 2002, this Task Group reviewed evidence for a number of health effects, and updated the evidence regarding cancer. The conclusions and recommendations of the Task Group are presented in a WHO Environmental Health Criteria (EHC) monograph (WHO, 2007).

Following a standard health risk assessment process, the Task Group concluded that there are no substantive health issues related to ELF electric fields at levels generally encountered by members of the public. Thus the remainder of this fact sheet addresses predominantly the effects of exposure to ELF magnetic fields.
Short-term effects

There are established biological effects from acute exposure at high levels (well above 100 µT) that are explained by recognized biophysical mechanisms. External ELF magnetic fields induce electric fields and currents in the body which, at very high field strengths, cause nerve and muscle stimulation and changes in nerve cell excitability in the central nervous system.
Potential long-term effects

Much of the scientific research examining long-term risks from ELF magnetic field exposure has focused on childhood leukaemia. In 2002, IARC published a monograph classifying ELF magnetic fields as "possibly carcinogenic to humans". This classification is used to denote an agent for which there is limited evidence of carcinogenicity in humans and less than sufficient evidence for carcinogenicity in experimental animals (other examples include coffee and welding fumes). This classification was based on pooled analyses of epidemiological studies demonstrating a consistent pattern of a two-fold increase in childhood leukaemia associated with average exposure to residential power-frequency magnetic field above 0.3 to 0.4 µT. The Task Group concluded that additional studies since then do not alter the status of this classification.

However, the epidemiological evidence is weakened by methodological problems, such as potential selection bias. In addition, there are no accepted biophysical mechanisms that would suggest that low-level exposures are involved in cancer development. Thus, if there were any effects from exposures to these low-level fields, it would have to be through a biological mechanism that is as yet unknown. Additionally, animal studies have been largely negative. Thus, on balance, the evidence related to childhood leukaemia is not strong enough to be considered causal.

Childhood leukaemia is a comparatively rare disease with a total annual number of new cases estimated to be 49,000 worldwide in 2000. Average magnetic field exposures above 0.3 μT in homes are rare: it is estimated that only between 1% and 4% of children live in such conditions. If the association between magnetic fields and childhood leukaemia is causal, the number of cases worldwide that might be attributable to magnetic field exposure is estimated to range from 100 to 2400 cases per year, based on values for the year 2000, representing 0.2 to 4.95% of the total incidence for that year. Thus, if ELF magnetic fields actually do increase the risk of the disease, when considered in a global context, the impact on public health of ELF EMF exposure would be limited.

A number of other adverse health effects have been studied for possible association with ELF magnetic field exposure. These include other childhood cancers, cancers in adults, depression, suicide, cardiovascular disorders, reproductive dysfunction, developmental disorders, immunological modifications, neurobehavioural effects and neurodegenerative disease. The WHO Task Group concluded that scientific evidence supporting an association between ELF magnetic field exposure and all of these health effects is much weaker than for childhood leukaemia. In some instances (i.e. for cardiovascular disease or breast cancer) the evidence suggests that these fields do not cause them.
International exposure guidelines

Health effects related to short-term, high-level exposure have been established and form the basis of two international exposure limit guidelines (ICNIRP, 1998; IEEE, 2002). At present, these bodies consider the scientific evidence related to possible health effects from long-term, low-level exposure to ELF fields insufficient to justify lowering these quantitative exposure limits.
WHO's guidance

For high-level short-term exposures to EMF, adverse health effects have been scientifically established (ICNIRP, 2003). International exposure guidelines designed to protect workers and the public from these effects should be adopted by policy makers. EMF protection programs should include exposure measurements from sources where exposures might be expected to exceed limit values.

Regarding long-term effects, given the weakness of the evidence for a link between exposure to ELF magnetic fields and childhood leukaemia, the benefits of exposure reduction on health are unclear. In view of this situation, the following recommendations are given:

* Government and industry should monitor science and promote research programmes to further reduce the uncertainty of the scientific evidence on the health effects of ELF field exposure. Through the ELF risk assessment process, gaps in knowledge have been identified and these form the basis of a new research agenda.
* Member States are encouraged to establish effective and open communication programmes with all stakeholders to enable informed decision-making. These may include improving coordination and consultation among industry, local government, and citizens in the planning process for ELF EMF-emitting facilities.
* When constructing new facilities and designing new equipment, including appliances, low-cost ways of reducing exposures may be explored. Appropriate exposure reduction measures will vary from one country to another. However, policies based on the adoption of arbitrary low exposure limits are not warranted.

Further reading

WHO - World Health Organization. Extremely low frequency fields. Environmental Health Criteria, Vol. 238. Geneva, World Health Organization, 2007.

IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. Non-ionizing radiation, Part 1: Static and extremely low-frequency (ELF) electric and magnetic fields. Lyon, IARC, 2002 (Monographs on the Evaluation of Carcinogenic Risks to Humans, 80).

ICNIRP - International Commission on Non-Ionizing Radiation Protection. Exposure to static and low frequency electromagnetic fields, biological effects and health consequences (0-100 kHz). Bernhardt JH et al., eds. Oberschleissheim, International Commission on Non-ionizing Radiation Protection, 2003 (ICNIRP 13/2003).

ICNIRP – International Commission on Non-Ionizing Radiation Protection (1998). Guidelines for limiting exposure to time varying electric, magnetic and electromagnetic fields (up to 300 GHz). Health Physics 74(4), 494-522.

IEEE Standards Coordinating Committee 28. IEEE standard for safety levels with respect to human exposure to electromagnetic fields, 0-3 kHz. New York, NY, IEEE - The Institute of Electrical and Electronics Engineers, 2002 (IEEE Std C95.6-2002).
For more information contact:

WHO Media centre
Telephone: +41 22 791 2222
E-mail: mediainquiries@who.int

You've discovered one source of information that supports your views and there are countless others, but there are also studies that show health issues exist.

It would be foolish to accept and believe what we read or download on the basis of a few letters after someones name.

Does a specialist in an office know more about the issues than the person living next to a turbine?

Let's not forget the specialists who've made so many great decisions in the past.

- Asbestos (no safety issues)
- Myxomatosis (Intentionally introduced by humans - how stupid!!)
- Leaky homes (She'll be right)

Aren't those specialists great?

Let's take the side of caution and look at the facts before jumping on the first WHO report and living in blind faith that it won't affect us.

Personally I am not worried about the ELF. Many studies look at the noise generated by the turbines but this is not the key issue either. It is the low frequency vibration that is cuasing most concern both nationally and internationally. There are several things to note on this too. Maybe there is not enough body of research yet on this to be definitive but why do we have to wait to find out for sure when the questions are already being raised - our history is littered with things that show that hindsight is a wonderful thing - UV, asbeston, thalidomide, global warming, greenhouse gases ...... Do we have to wait and say again "Ooops got it wrong!" If there was no basis for all of this then why is there so much debate and so many international conferences and so many reports on the negative impacts on people. It is hard, agreed, to tell sometimes if the concerns are real or perceived but for those people who perceive it then it is very real to them. A study of the impacts on people in the area near Te Apiti certainly suggests that it is a real concern to them.

I suggest you do some research now, and find the studys ( that are of some merit, not the result of some biased survey or similar ) that show a health risk from ELF, and provide links to them, so we can see them.

PS. If I follow your logic " it woudl be foolish to accept them " as well, as if they are of any worth, they almost invariably will have been done by people with " a few letters after their name "

PPS. I'm guessing you don't have a few letters after your name. If you worked hard to get some, you woudn't be so flippint.

ELF in my opinion is a pretty much a non issue.

Noise is almost a non issue. The design of this generation of mills, has drastically reduced noise. a noisy windmill is an un-efficient windmill.. And much work has been done to get as much out of the mills as possible... The numbers are very measurable, and quantifable. There maybe some people who might hear them from their homes.. perhaps.. I'm sure that RES NZ, will be able to provide this data. I suggest that you go the open day- Nov 3, at the anchor church in Whitby. ( 10-4pm ) and ask them to provide this data.

The LF vibration is of real concern, and this issue needs addressing. LF vibration can travel a long way, depending on the geography and design of the mill, the wind conditions etc. I lived next to a large diesel generator for a few months, that supplyed power to where i was working/living.. It was quiet.. but you knew when it was running and it was'nt plesant.. However theres mechanisms to fix this.. They do it in large buildings all the time now, they move around and sway back in forward otherwise.. and the same effect comes into play..

Now I have become confused - I was not being flippant about ELF radiation in general - only related to the wind turbines - as in I am not worried about ELF radiation from a wind turbine - which you have now said is a nonissue!! I also agree that audible noise is likely to also be a nonissue for it seems to me that all measures of audible noise indicate that the turbines are unlikely to exceed the limits set. I do have concerns regarding low frequency vibration as all I have read indicates that this is an issue - and it was this that I was referring to when I said about a lack of understanding about the long term implications and also that people's perceptions can vary regarding how much it impacts on them. I do not pretend to understand about wind farms, energy generation etc - not all of us are experts in this area. The number of letters after my name (before my name or anywhere else actually) are totally irrelevant for not all of us can expect to be experts in every field of human endeavour. We can however be open to learning about issues that are going to have a major impact on our lives. And I am not naive enough to believe everything that is put out by the wind farm developers - for I believe that they are motivated as much by economics and profit margins as by any intent to be "clean and green" or to look after the interests of those in our community. I may sound like a NIMBY (maybe I should use those letters after my name in this forum!!!!) but if I cannot look after my own backyard then I am certainly not going to do a very good job anywhere else.

Hi Diane, my comment about flippancy was in reference to TK461's comment about a few 'letters' after someones name. Quite unhelpful in-deed.

I'm no expert in wind-generation either, but i'm learning quickly, by taking the time to reseach, read and try to understand what the real issues are, so that i can make informed and sensible comment.


the LF vibration issue is real from what i can find. However like the noise issues of the past in windmill design, theres been a lot of work to fix this.. Not because LF annoys people who are in the proximity of the mill. Its because a mill that causes lots of vibration is inefficent. To move the ground requires a lot of energy, which is energy that is being wasted, rather than generating electricty. Technology has got a lot better than the mills of 20 30 40 and 50 years ago.

I agree that the motiviation of the wind-farmers is primarly economics. They want to make a profit. If i was speding that much, so would i. I certainly can see past the spin of that.

I hope if nothing else, sensible discussion of 'real facts', will allow people to make informed conclusions, and submissions rather than comment based on fear and misunderstanding.. Of which i belive both sides ( the windfarmers and the NIMBYS ) are both spinning up..

Oops sorry about that - I think my reading of the posts obviously crossed over somewhere - my apologies. Yes I agree that we need informed information - the difficulty at present is sifting and sorting it and working out what is the most valid - I also come back though to the fact that sometimes it is hard to predict exactly what will happen - noise/vibration being two of these (the montages can give an idea of the visual impacts) but with noise and vibration even the experts do not seem to agree. Maybe the fact that it is still being so vigorously debated should make us err on the side of caution.

There was some very low frequency noise on Labour Day that could be heard from a number of places in Pauatahanui. Could have been coming from anywhere as low frequency noise is hard to track but it does show that it travels and can be felt over and above other background noise.

Earthquake? They rumble nicely..

Plenty of weedeaters and lawn-mowers where out on Monday as well.. We had the rotaryhoe going, then had to dig a couple of postholes.. ( sigh, lifesytle block = lifesentance block, but who woudl want to live in the city? )...

When you say number of places, how localised where they?

Earlier in this discussion 6phr mentioned about lf vibration - so what are considered reasonable distances to have turbines located from dwellings? given that they do have the potential (from all I have read) to create this? Also how is it measured? People talk about noise measurements but this is different - isn't it?

its pretty simple maths..

The more its vibrating, the further away it will be felt.. so, the newer mills which vibrate considerabley less, its not far away at all. You might be lucky to detect the mill jsut a few meters away from its base..

No if a blade gets off-balance... you'll get heaps of vibration.. but the new mills shut themselves down pretty quickly in this situation, becuase they will self destruct if they go on shaking..

I reinforce my previous point.. No windmill operator will be happy about vibrations in the ground.. Thats all energy that should be going to produce electicty.

Very presumptuous to say that the math is simple. Indeed it is anything but. Consider the variations in soil substrate, the combination of frequency from each turbine and collectively. Terrain, geographical obstructions, style of buildings. Depending on the depth of soft soil on hard rock, the effects may increase with distance, as seen in tsunamis. Both amplitude and frequency need to be considered. The effort and subsequent cost of analysis are almost certainly not going to be invested by wind energy developers to mitigate discomfort to residence.

While I accept that the energy companies will minimise vibration where it is cost effective and demonstrates a measurable drop in power output, there would be no financial or other incentive to do so just to make it nice to live near. These guys are in it for the money. Period.

You are implying that the vibration occurs from "shaking" if I read you right but I thought the vibration was more like that from music where you may not hear the music loudly but you can still "hear"/feel the thump???? I would have thought that the 400-plus cu metres of concrete at the base of each one would effectively stop any actual vibration - not that one could consider that amount of concrete very "clean and green"....

Suggest you go research what math is required to calculate the amplitude of the vibration at any given point. Then come back and tell me its not simple. Still waitign for the references to the papers that show that ELF is a health risk that you mentioned a while back??

We'll always find what we're looking for. Simply searching Google will give you most of the answers and while there is a great deal of dross on the web, much of the information comes from credible sources.

What is clear though, is that pro-wind information is almost exclusively from commercial benefactors or green fanatics. Not that this should be a surprise.

The acoustic noise radiation (especially its infrasonic part) is one of the wind turbine quality parameters.

Principal sources of a wind turbine noise:
- mechanical noise from transmission , multiplier (multiplying wheels), generator;
- discrete frequency noise at the blade passing frequency and its harmonics,
- aerodynamic noise: trailing edge noise, separation – stall noise, tip vortex formation noise,
laminar boundary layer vortex shedding noise, trailing edge bluntness vortex shedding noise,
- noise due to turbulent inflow.

Wind disturbs the general level of noise measurements. To diminish the wind influence the
measurements are carried on at the reflection or absorption earth plane.

We can generalise the statistic data about wind turbine noise measurements and obtained the next
empiric equation for wind turbine acoustic power:

Lw8 = 0.013 ( lgW)2 + 7.4648 lgW + 82.418
Lw8 = 75 + 17.2 D
Lw(V) = Lw8 – 6.64 + 0.83 V
Lw(V,D) = 68.36 + 17.2 lgD +0.83V ,

where
Lw8 - wind turbine acoustic power (in decibel) at the wind velocity V = 8 m/sec,
D – wind turbine windwheel diameter (in meter),
W- wind turbine power (in kilowatt).

Achieved empiric equation can be used for wind turbine, which has a horizontal main shaft and
three blades.

Simple math?

I also found this article of interest.

http://www.viewsofscotland.org/libr...alth-1.pdf

Yes simple maths indeed..

I can't see the link to what you were talking about in your last post though, and how this relates to it.

(1) "pro-wind information" - imho information is just that, not pro or anti something.. conclusions and opinions can be pro/anti something.

(2) Could you clarify how you came to your conclusion on the source of "pro-wind information". Statements with backup and reference are worth noting. Statements without any substance, tend to blow around in the wind.. ( no pun in reference to windmills intende )

You're entitled to your own opinion, as we all are. I personally want to know as much as I can about the potential adverse impacts of wind turbines so that I can act accordingly. My personal research indicates that this is the right step to take. While it's encouraging that you're also showing an interest and I welcome your points, I don't believe anyone should prevent others from reaching their own conclusions.