Noise pollution alters ecology

It must be no surprise to anyone that noise pollution can and does affect ecology, the local balance of flora and fauna, including human beings. There is now conclusive documentation of the effects of noise on ecology through a careful study of bird and seed in a remote area. Noise pollution “may have dramatic long-term effects on ecosystem structure and diversity“. Because the extent of noise pollution is growing, this study emphasizes that “investigators should evaluate the ecological consequences of noise alongside other human-induced environmental changes that are reshaping human-altered landscapes worldwide“.

The natural world deserves our careful stewardship through comprehensive environmental impact assessment of industrial projects. Of the many dozens of environmental impact statements I have reviewed over the years, there has been essentially no consideration of the effects of noise on ecology. Perhaps this study, and others, will serve as a caution that noise is a truly significant pollutant capable of adversely affecting ecology.

For more information, visit Noise pollution alters ecological services: enhanced pollination and disrupted seed dispersal.

The costs of chronic noise exposure for terrestrial organisms

A recent technical paper[1] reviews findings from a number of research studies of the effects of chronic noise exposure for terrestrial organisms. Drawing from fully one hundred references, the findings describe noise effects on every organism studied.

Chronic noise exposure is widespread. Taken individually, many of the papers cited here offer suggestive but inconclusive evidence that masking is substantially altering many ecosystems. Taken collectively, the preponderance of evidence argues for immediate action to manage noise in protected natural areas. …

It is clear that the acoustical environment is not a collection of private conversations between signaler and receiver but an interconnected landscape of information networks and adventitious sounds; a landscape that we see as more connected with each year of investigation. It is for these reasons that the masking imposed by anthropogenic noise could have volatile and unpredictable consequences. …

The costs of noise must be understood in relation to other anthropogenic forces, to ensure effective mitigation and efficient realization of environmental goals. Noise pollution exacerbates the problems posed by habitat fragmentation and wildlife responses to human presence; therefore, highly fragmented or heavily visited locations are priority candidates for noise management. Noise management might also offer a relatively rapid tool to improve the resilience of protected lands to some of the stresses imposed by climate change. Shuttle buses and other specialized mass transit systems, such as those used at Zion and Denali National Parks, offer promising alternatives for visitor access that enable resource managers to exert better control over the timing, spatial distribution, and intensity of both noise and human disturbance. Quieting protected areas is a prudent precaution in the face of sweeping environmental changes, and a powerful affirmation of the wilderness values that inspired their creation.

1. Jesse R. Barber, Kevin R. Crooks, and Kurt M. Fristrup. “The Costs of Chronic Noise Exposure for Terrestrial Organisms” Trends in Ecology and Evolution 25.3 (2010): 180-189.

Land-Based Wind Energy Guidelines

The U.S. Fish and Wildlife Service has been working on guidelines to protect wildlife from wind turbine noise emissions for several years. The “Wind Turbine Guidelines Federal Advisory Committee” has submitted recommendations which have been included in a draft document. A quick read suggests that the guidelines are voluntary and that no specific limits on noise levels or changes over background are included in the draft. While the Service “intends that these Guidelines, when used in concert with the appropriate regulatory tools, will be the best practical approach for conservation of species of concern,” it is arguable that voluntary guidelines provide little or no assurance of species protection.

Sound and Wildlife [1]

Turbine blades at normal operating speeds can generate levels of sound beyond ambient background levels. Construction and maintenance activities can also contribute to sound levels by affecting communication distance, an animal‟s ability to detect calls or danger, or to forage. Sound associated with developments can also cause behavioral and/or physiological effects, damage to hearing from acoustic over-exposure, and masking of communication signals and other biologically relevant sounds (Dooling and Popper 2007). Some birds are able to shift their vocalizations to reduce the masking effects of noise. However, when shifts don’t occur or are insignificant, masking may prove detrimental to the health and survival of wildlife (Barber et al. 2010). Data suggest noise increases of 3 dB to 10 dB correspond to 30 percent to 90 percent reductions in alerting distances for wildlife, respectively (Barber et al. 2010 [2]).

The National Park Service has been investigating potential impacts to wildlife due to alterations in sound level and type. However, further research is needed to better understand this potential impact. Research may include: how wind facilities affect background sound levels; whether masking, disturbance, and acoustical fragmentation occur; and how turbine, construction, and maintenance sound levels can vary by topographic area.

As can be seen in the draft document text provided above, the Service acknowledges serious adverse impact potentials yet appears to take the approach of “more research” and using post-construction monitoring to assess wildlife impacts. Since distance set during permitting is the only reliable option for wind turbine noise control at this time, the “post-construction monitoring” advocated by the Service may serve to document adverse impacts on species but provides limited utility for species protection. In plain language, once wind turbines are installed and running, the only way to “mitigate” adverse wildlife impacts is to turn off the wind turbines, degrading the wind facility financial basis (an option likely to be met with vigorous opposition by the facility owners).

Proper siting is essential. “Alternative” energy systems based on solar or wind may work as legitimate power engineering options if positive or net-black cost benefit ratios can be established for production and environmental costs. It is suggested here for reader consideration that impacts on species might be reduced were wind turbines sited near busy urban areas compared to ultra-quiet wilderness and quiet rural areas. However there remain serious and unanswered questions about the health effects of low-frequency pulsations from wind turbines, which grow lower in frequency as wind turbines get larger.

We trust, do we not, that we have learned from our former ignorance of environmental impacts during the past many decades, starting with DDT (Silent Spring, Rachel Carson). The bar is set higher now, is it not, from our having learned that we must be honest, transparent, and un-biased to political and corporate interests that in the past, at least, were uninterested in environmental protections. However, once again, consternation surfaces, as separately, questions have been raised as to possible political bias in the committee itself:

“The new guidelines would harm birds by only giving U.S. Fish and Wildlife Service (FWS) biologists responsibility to review wind projects within new, truncated deadlines, and without the funding to hire the requisite additional staff. The new draft guidelines would also protect fewer migratory birds than the earlier version and move away from DOI’s legal responsibility to protect all migratory bird species, not just ‘species of concern’.”

In addition, the new guidelines remove protections for both birds and people that FWS biologists had recommended in their peer-reviewed guidelines, including:

• Allowing greater latitude in installing overhead power lines between wind turbines, which increases the risk to larger birds such as eagles, hawks, and cranes, instead of burying the lines.

• Removing a recommendation that wind developers address wildfire risk and response planning, something that could be potentially very important, especially in Western communities or areas experiencing drought.

• Removing a recommendation that wind developers avoid discharging sediment from roads into streams and waters, a standard recommendation at construction sites that protects water quality.

• Removing a recommendation to avoid active wind turbine construction during key periods in the life histories of fish and wildlife, such as the nesting season for migratory birds.

Will the Service ensure that political and corporate interests are held at bay during this important process?

Concerned citizens have until August 4 to comment on the current guidelines. Comments can be sent to



2. Jesse R. Barber and Kurt M. Fristrup. “Evaluating the Prevalence of Masking as a Causal Factor in Wildlife Responses to Noise” Acoustical Society of America. Baltimore, MD. Apr. 2010.

The human stapedius-muscle

The proliferation of wind turbines in the US has led me progressively further into the human auditory system’s mechanics and further, into the neuroscience of hearing. This is an absolutely fascinating realm, especially so when uncovering the gradual changes in scientific understanding of how the ear hears. Of course the “ear” is not just what we see on the outside of the head. Hearing goes all the way from the outer ear deep into the mysterious workings of our plastic brain.

This web site below surfaced today during a search about the stapedius-muscle reflex. I highly recommend it. While much of it may feel dense at first, reading this article is a lot like spelunking in a cave, uncovering brilliant gems of information about one of the most miraculous gifts we have been given as humans- our hearing. My interest, of course, is in the effects of very low frequency sound (such as that emitted by wind turbines) on human physiology.

The stapedius-muscle contraction reduces sound transmission at low sound frequencies at higher sound pressure levels. Does the stapedius-muscle reflex fire off when moderately intense infrasonic pulsations repeatedly enter the ear? It’s not clear if it does. If it doesn’t fire off, thereby leaving the inner ear open to higher pressure levels from infrasonic pulsations, could that play a role in gradual and cumulative dose-response impacts on the vestibular organs, such as vertigo, dizziness, even nausea? The stapedius-muscle reflex is one of several ways that the auditory system protects the inner ear. Are there other ways that infrasonic pulsations might bypass these protections and induce inertial movements in the vestibular organs (whose primary role is to sense their own movement)? Is it appropriate to say “no” without proof that these potentials do not exist?

Auditory system: Peripheral nonlinearity and central additivity, as revealed in the human stapedius-muscle reflex.

Ultrasonic security systems

Have you felt or heard something funny at the local pharmacy or department store? Like a high pitched whine or pressure in your head? Not sure what it was? It could be their ultrasonic intrusion sensors. Intrusion sensors are normally active during off-hours to detect unwanted, er, intruders. One would think that these would be shut off during business hours, because, well, people go shopping. Doh!

I encountered an ultrasonic detection system unexpectedly at a local Sears store this week. As I walked into the tools section, I experienced a very uncomfortable buzzing sensation between my ears that felt, well it felt like my brain was being sawed in two. It was disturbing. However, having recently encountered unexpected discomfort near a sound source (see my post on Hammered by a wind turbine), I backed off quickly and fired up the iPhone SignalScope application. I walked toward the previous location with SignalScope running and captured a 21 kilohertz signal that peaked in intensity right at the spot where I had experienced the strongest and most uncomfortable sensations. Bingo! It was an active ultrasonic volumetric motion or “occupant” detector system- running during daytime hours.

Did other people hear or feel it? My sweetheart said she felt a pressure on her head at that location. The sales associate was cordial but heard nothing.

It’s worth noting that a standard sound level meter, even a Type 1 Precision sound level meter, wouldn’t register this acoustic tone at all. Depending on the model, sound level meters cover from 20 Hertz to 20,000 Hertz. This security system tone falls outside sound meter range!

So- if you’re in a store and suddenly feel a really strange sensation in your head, it’s probably not your imagination or something you ate. It’s probably the store’s ultrasonic security system!

An ultrasonic sensor is volumetric, meaning it floods an area within its coverage pattern. This allows it to detect persons behind partitions and other obstructions. Any moving object within its coverage area will disturb the sound wave pattern, creating a Doppler shift and altering the signal returning to the sensor. False activation may also occur from vibration, air movement, high sound levels, and audible sounds having ultrasonic components. Ultrasonic sensors have sensitivity adjustments to minimize environmental effects. Reducing sensitivity will also reduce the coverage area. If ultrasonic sensors are mounted close to each other, they must operate at different frequencies to avoid interfering with each other.

Plasticity in the Auditory Brainstem

Excerpt from this neuroscience article. Basically, what this article says is that we know now from research of the last ten years or so that the auditory system is not a fixed system. It responds to changes in the auditory environment. Our hearing is not hard-wired like sound level meters. Our hearing is highly adaptable.

Contrary to traditional views that early stages of sensory processing are not plastic, new studies discussed in this article have established that the auditory brainstem is dynamic. The plethora of intrinsic and synaptic plasticity mechanisms observed in the auditory brainstem in combination with the noninvasive methods of assessing auditory brainstem function in humans provides a platform for relating subcortical auditory processing to higher-order sensory and cognitive tasks involving speech and music. Therefore, we suggest that the auditory brainstem offers an ideal model to study the mechanisms and functions of nontraditional aspects of sensory processing, such as synaptic and intrinsic plasticity and recurrent feedback from higher levels of processing.

The past 10 years of research have revealed how timing information is fed through auditory brainstem pathways. This research has provided insight into how sounds are localized by vertebrates, but much less is known about how these pathways adapt to ongoing sensory activity and how they contribute to the perception and interpretation of environmental sounds, including speech, under normal and pathological conditions. Therein lies the exciting future of revealing the role of plasticity observed in the auditory brainstem.

Whether activity-dependent changes are initiated/modulated in a topdown fashion, as predicted by the RHT [Reverse Hierarchy Theory, Ahissar and Hochstein, 2004, ed.] through the efferent, corticofugal system linking the cortex and the auditory brainstem; through local mechanisms of adaptation to the acoustic properties of the input (Dean et al., 2005); or through an interaction of afferent and efferent mechanisms is a challenge for future research to resolve.

How many people have vestibular disorders?


The exact number of people affected by vertigo/dizziness/imbalance is difficult to quantify. In part, this is because symptoms are difficult to describe and differences exist in the qualifying criteria within and across studies. However, broad-based demographic studies consistently show that vestibular disorders are underdiagnosed and undertreated.

“From 2001 through 2004, 35.4% of US adults aged 40 years and older (69 million Americans) had vestibular dysfunction.” [1]
Dizziness is a common symptom affecting about 30% of people over the age of 65.4. [2]
“U.S. doctors reported 5,417,000 patient visits in 1991 because of dizziness or vertigo.” [3]
“Approximately four percent (almost eight million) of American adults report a chronic problem (lasting three months or longer) with balance, while an additional 1.1 percent (2.4 million) of American adults report a chronic problem with dizziness alone.” [4]
“Vestibular vertigo accounts for one-third of dizziness/vertigo symptoms in the medical setting.” [5]
“Research on the personal and health care burden of ill health usually focuses on specific diseases rather than symptoms. This diagnosis-based approach may underestimate the burden of common symptoms such as dizziness and vertigo, which rank among the most frequent complaints in primary care but remain unexplained in 40% to 80% of cases.” [5]
“Despite reports that, as a consequence of vestibular deficits, children have poor gaze stability that affects reading, and impairments of motor development and balance, children are not typically screened for vestibular deficits. Consequently, vestibular dysfunction is an overlooked entity and intervention to ameliorate these impairments is not provided.” [6]

How do vestibular disorders/vertigo/dizziness/imbalance affect people’s quality of life?
“A majority of individuals over 70 years of age report problems of dizziness and imbalance, and balance-related falls account for more than one-half of the accidental deaths in the elderly…Furthermore, in a sample of persons age 65-75, one-third reported that dizziness and imbalance degraded the quality of their lives.” [1]
“Difficulty in performing one or more activities of daily living (bathing, dressing, eating, getting in and out of bed, using toilet, getting around inside home) is highly prevalent among adults with chronic balance or dizziness: 11.5% with chronic dizziness, and 33.4% with chronic balance.” [7]
“People with measured vestibular dysfunction who are also symptomatic have a nearly 8-fold increase in the odds of falling compared with people neither of these risks. People with vestibular dysfunction who are asymptomatic also had significantly increased odds of falling.” [2]
“Falls are the leading cause of fatal and non-fatal injuries for persons age >65 years.” [8]

How do vestibular disorders impact health care systems?
“Overall, the cost of medical care for patients with balance disorders exceeds $1 billion per year in the United States.” [4]
“In the general population (all ages), 347,000 hospital days [per year in the U.S.] are incurred because of ‘vertiginous syndromes,’ 202,000 because of ‘labyrinthitis’ and 184,000 because of ‘labyrinthitis unspecified,’ with several thousands more accounted for by other balance disorders, e.g., Meniere’s disease.” [9]
Patient care costs for falls are more than $8 billion per year. [4]

What is the most common vestibular disorder?
Most experts regard BPPV as the most commonly diagnosed vestibular disorder. It accounts for at least 20 percent of diagnoses made by doctors specializing in dizziness and vestibular disorders. It is the most frequent cause of vertigo in the elderly. The number of people affected by this disorder each year has been estimated between 10 per 100,000 and 64 per 100,000 people, and some experts feel even more may be affected. [10],[11]

Recent epidemiological studies in Germany and Japan suggest BPPV accounts for somewhere between 7% and 8% of all causes of vertigo. The German study further states that although 86% of people with BPPV undergo medical consultation, interruption of daily activities, or sick leave, only 8% receive effective treatment. [12],[13]

How many people have Meniere’s disease?
The exact number of people with Meniere’s disease is difficult to measure accurately because no official reporting system exists. Numbers used by researchers differ from one report to the next and from one country to the next. The National Institutes of Health estimates that about 615,000 people in the US have Meniere’s disease and that 45,500 new cases are diagnosed each year. [14]

How is the Vestibular Disorders Association (VEDA) helping?
VEDA answers thousands of e-mails and calls each year from people with questions about vestibular disorders.
Each year, approximately 600,000 people pour over 2 million pages of information from our Web site.
Each month, nearly 16,000 people access our provider directory of health care professionals who specialize in vestibular disorders.
Information is most frequently requested from VEDA about the following topics: labyrinthitis, Meniere’s disease and endolymphatic hydrops, benign paroxysmal positional vertigo (BPPV), and ototoxicity.


1. Agrawal Y, Carey JP, Della Santina CC, Schubert MC, Minor LB. Disorders of balance and vestibular function in US adults. Arch Intern Med. 2009;169(10):938-944.

2. Colledge N, Lewis S, et al. Magnetic resonance brain imaging in people with dizziness: a comparison with non-dizzy people. J Neurol Neurosurg Psych. May 2002;72(5):587-589.

3. Centers for Disease Control and Prevention. Vital and health statistics, national ambulatory medical care survey: 1991 summary. Washington, DC: National Center for Health Statistics, Public Health Service, US Dept of Health and Human Services; 1994. DHHS publication PHS 94-1777.

4. National Institute on Deafness and Other Communication Disorders (NIDCD). Strategic plan (FY 2006-2008). Available online. Accessed June 12, 2009.

5. Neuhauser HK, Radtke A, von Brevern M, Lezius F, Feldmann M, Lempert T. Burden of dizziness and vertigo in the community. Arch Intern Med. 2008;168(19):2118-2124.

6. Rine RM. Growing evidence for balance and vestibular problems in children. Audiological Med. 2009;7(3):138-142.

7. Ko C, Hoffman HJ, Sklare DA. Chronic Imbalance or Dizziness and Falling: Results from the 1994 Disability supplement to the national health interview survey and the second supplement on aging study. Paper presented at: Annual Meeting of the Association for Research in Otolaryngology. February 6, 2006; Baltimore, MD.

8. Self-reported falls and fall-related injuries among persons aged >65 years—United States, 2006. MMWR Morb Mortal Wkly Rep. 2008;57:225-229.

9. National Institute on Deafness and Other Communication Disorders. National strategic research plan—1991, 1992, 1993. Washington, DC: US Department of Health and Human Services; Public Health Service, US Dept of Health and Human Services; 1994. NIH Publication No. 95-3711.

10. Froehling DA, Silverstein MD, Mohr DN, Beatty CW, Offord KP, Ballard DJ. Benign positional vertigo: incidence and prognosis in a population-based study in Olmsted County, Minnesota. Mayo Clin Proceedings. 1991;66(6):596-601.

11. Mizukoshi K, Watanabe Y, Shojaku H, Okubo J, Watanabe I. Epidemiological studies on benign paroxysmal positional vertigo in Japan. Acta Otolaryngologica. 1988; 447(suppl):67-72.

12. von Brevern M, Radtke A, Lezius F, Feldmenn M, Ziese T, Lempert T, Neuhauser H. Epidemiology of benign paroxysmal positional vertigo: a population based study. J Neurol Neurosurg Psych. 2007;78:710-715.

13. Yin M, Ishikawa I, Wong WH, Shibata Y. A clinical epidemiological study in 2169 patients with vertigo. Aurus Nasus Larynx. 2009;36:30-35.

14. National Institute on Deafness and Other Communication Disorders. Meniere’s disease. Available online. Accessed February 25, 2010.

Hammered by a wind turbine

I got surprised last week (April 17-19, 2011) on a wind turbine noise survey with my long-time colleague Steve Ambrose, also a Member of INCE. We experienced all the symptoms described by folks unfortunate enough to live nearby where an industrial wind turbine facility has been built. Nausea, loss of appetite, vertigo, dizziness, inability to concentrate, an overwhelming desire to get outside, and anxiety.

The distance was approximately 1700 feet from one 1.65MW industrial wind turbine.

We obtained relief, repeatedly, by going several miles away.

Vertigo came back much stronger for me today, a week later, simply while reviewing the precision audio recordings from the trip on small laptop speakers. Moderate nausea coming and going, and ears ringing and feeling full. That may mean that I have been “sensitized” and I’m now more susceptible to the symptoms.

If you’ve ever been seasick, or travel-sick on planes, you might understand the feeling.

Et, en Francais-