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CAOHC Newsletter: UPDATE

The Booming Sound of Safe Energy: Health Effects from Low Frequency Noise Exposures from Wind Farms

Sean Navarrette

Introduction

There are many reasons behind the popularization of wind energy. Gasoline production is expensive. Coal burning is not clean. Nuclear power is dangerous. We are dependant on a constant and reliable supply of energy to survive. Therefore, wind energy is becoming a more and more appealing substitute because it offers a pollution free, waste free, cheap and renewable alternative to current major energy options such as fossil fuel, coal, and nuclear energy.

The U.S. Department of Energy (DOE) defines wind energy as a “form of energy conversion in which turbines convert the kinetic energy of wind into mechanical or electrical energy that can be used for power”. The DOE estimates that the U.S. has the “wind resource potential” to power our country 10 times over per year (DOE, 2011). Currently, our nation produces approximately 40,000 megawatts per year, which accounts for roughly 2% of our electricity generated (DOE, 2011). According to the American Wind Energy Association (AWEA), there are six states in the U.S. that produce more than 5% of their energy using wind power, with Iowa leading the group at more than 14%.

Despite the obvious advantages of wind energy, the proliferation of wind farms can result in increased exposure to low frequency noise, which can have adverse health effects to humans.

Low Frequency Noise (LFN) Pollution

Wind energy may be cause for concern as it pertains to noise pollution, specifically low frequency, sometimes “sub-audible” noise which can cause adverse effects on human health. The AWEA, for example, states that “sub-audible, low frequency sound and infrasound from wind turbines do not present a risk to human health” and “does not pose a risk of hearing loss or any other adverse health effect in humans,” while other groups such as the Society for Wind Vigilance propose that “exposure to audible low frequency noise can cause adverse health effects in humans,” adding that “annoyance is acknowledged as an adverse health effect” (windvigilance.com). Pawlaczyk-Luszczynska et al. (2010) associate this annoyance with “disturbance, irritation, discomfort, dissatisfaction, bother, nuisance, uneasiness and distress” and was shown to cause adverse effects on humans in a laboratory setting. As a result, widespread complaints and lawsuits have increased alongside the growing number of wind farms on the basis of adverse physiological effects, decreased property value, and overall ruin of an area’s natural aesthetic (Zeller, 2010).

Low frequency noise (LFN), sometimes referred to as infrasound, is at the center of the noise pollution debate concerning wind energy. Though it is often referred to as sub-audible noise, this type of sound can still have an adverse effect on human health, particularly those more sensitive to sound. Simply put, LFN typically exists in the 10 Hertz (Hz) to 200 Hz range. Most young, healthy humans can hear within the 20 Hz to 20,000 Hz (or 20 kHz) range. So while LFN is on the lower end of the human sound range it can still be heard even if it is not immediately noticed. For example, in an office setting, employees may hear the air pass though vents of the central air conditioner unit at a low frequency range but may not notice the sound until the air conditioner is turned off.

No regulations exist for LFN, even though most U.S. agencies have adopted the idea that LFN can have adverse health effects based on recent research. Additionally, Leventhall (2004) postulates that another problem with regulations pertaining to LFN is that using the A-weighted scale may be inappropriate in the case of LFN as it is only part of the process and does not take into consideration those more susceptible to it effects.

The Public Health Debate

While wind energy may be one of the cleanest sources of energy, it’s clearly not without its own emissions. People living near wind turbines or wind farms – a collection of wind turbines strategically placed to maximize energy production – have reported symptoms including but not limited to sleep disturbances, irritability, chronic headaches, dizziness, depression, and stress (Mahendra & Sridhar, 2008). Problems may also arise with those working near or on wind farms.

Studies have shown occupational and industrial exposure to LFN may cause progressive symptoms such as sleep disorders, chronic fatigue, and repetitive aching in the head, back and neck (Mahendra & Sridhar, 2008). According to Mahendra and Sridhar (2008), the “physiology, hearing capability, auditory communication, and sleep of industrial workers were significantly affected by noise levels.” These outcomes are a result of continuous exposure to industrial settings such as factories. However, it was also noted in their study that in addition to the loudness of the noise, the impulse or frequency played a part and added to the “unpleasantness” (Mahendra & Sridhar, 2008). Another important thing to note is that these negative health effects are not just limited to employees themselves; persons living in the proximity of factories and wind turbines may experience the same health effects from the noise pollution emanating from these sources. Children, the elderly, and those more sensitive to LFN may be more at risk to these progressive symptoms.

The same kind of exposure has been shown to lower performance in working conditions. According to Waye et al. (2001), subjects ordered to carry out basic office-type work (i.e. verbal reasoning, proof reading, etc.) while being exposed to LFN similar to that of an office environment tended to perform at lower levels compared to a noise free environment. There are obvious implications to this study in an office setting, but the same effects could be seen as a result of LFN resonating from wind farms as well. This being the case, LFN from this source may not only affect performance in an occupational situation but also in a private or non-occupational situation. For example, children living in the close proximity of a wind turbine or wind farm may consequently see lower grades compared to those living in turbine free areas. In this study, those more sensitive to LFN were yet again shown to be at a disadvantage from a performance standpoint than those not sensitive (Waye et al., 2001).

Conclusion

While most people may not be affected by low frequency noise, to others it can be debilitating and severely disruptive to their lives at work and at home. Exposure to LFN can cause adverse health effects such as irritation, discomfort, overall dissatisfaction, and annoyance. Chronic exposure can lead to dizziness, depression, headaches and sleep disturbances.

Current clinical studies have focused on the adverse health effects of LFN. Despite the growing number of studies done, some gaps still exist in the research community pertaining to this topic. Several studies have been published on LFN, mainly in an office or industrial setting though few specifically in regards to residential effects from exposure to wind farms. While the frequency level (Hz) of LFN can be the same regardless of the source, very few studies have been published making the same connection to exposure symptoms and wind farms as with an office or industrial setting. Likewise, as Leventhall (2004) indicated most studies on LFN have been done measuring the exposure on the A-weighted scale even though additional methods may be more appropriate, which could potentially be an issue in terms of validity of past studies. Additionally, each study viewed referred to those more sensitive to LFN but no study could give a percentage of the general population that may fall into this category. Such a statistic may not currently exist for the U.S.

As the number of wind farms grows in the U.S., so too will the number of complaints concerning the lowering of property value, ruining of area’s natural aesthetic, and the exposure to LFN. That being said, a cost-benefit analysis performed by the EPA may be called for, along with additional research conclusively evaluation the relationship of the proximity to a wind farms to seriously adverse health effects such as depression and sleep deprivation. This way, a legitimate, unbiased government agency can produce a report weighing in the pros and cons of wind energy to the potential health effects. Obviously, more research is needed in this issue. Although the environmental benefits of using wind energy may far outweigh the negatives, it would be prudent to develop a strategy to manage the number of new wind turbines installed, and its proximity to humans.

For more information see the following websites; windeis.anl.gov and www.awea.org.

References:

DOE (2011). Wind and Water Power Program. Available at: http://www1.eere.energy.gov/windandhydro/pdfs/eere_wind_water.pdf, accessed on March 3, 2011.

Leventhall HG (2004). Low frequency noise and annoyance. Noise Health 6 (23):59-72

Mahendra Prashanth KV, Sridhar V (2008). The relationship between noise frequency components and physical, physiological and psychological effects of industrial workers. Noise Health 10(40):90-8

Pawlaczyk-Luszczynska M, Dudarewicz A, Szymczak W, Sliwinska-Kowalska M (2010). Evaluation of annoyance from low frequency noise under laboratory conditions. Noise Health 12(48):166-81

Waye KP, Bengtsson J, Kjellberg A, Benton S (2001). Low frequency noise “pollution” interferes with performance. Noise Health 4(13):33-49

Zeller T (2010). For Those Near, the Miserable Hum of Clean Energy. The New York Times. http://www.nytimes.com/2010/10/06/business/energy-environment/06noise.html?_r=2&nl=&emc=aua1, accessed on March 3, 2011

Sean Navarrette is a Masters of Public Health student at the University of Nebraska Medical Center in Omaha, Nebraska. His specific concentration is Health Service Administration. He graduated from the University of Nebraska – Lincoln in 2007 with a bachelor’s degree in Business Administration.