By Robert Bradley Jr. — September 14, 2021
Ed. Note: The health effects of industrial wind on local residents continues to attract mainstream research despite severe political incorrectness. It’s common sense: huge industrial machines moving in the open air have negative effects. For other posts at MasterResource on this subject, see here. This post complements yesterday’s on the nighttime amplification of noise.
“Wind turbines generate low-frequency noise (LFN, 20–200 Hz)…. [which causes] headaches, difficulty concentrating, irritability, fatigue, dizziness, tinnitus, aural pain sleep disturbances, and annoyance. Clinically, exposure to LFN from wind turbines may cause increased risk of epilepsy, cardiovascular effects, and coronary artery disease.”
“In order to reduce LFN transport from outdoors to indoors, we recommend that the windows should be kept closed, especially at nighttime because LFN is most noticeable at night. In addition, … residences in close proximity to wind turbines should be equipped with airtight windows.” (Nature, September 8, 2021)
Make no mistake: the obvious is becoming mainstream despite the protests of the mighty industrial-wind complex. The latest evidence on aerodynamic noise comes from Nature magazine [Scientific Reports volume 11: 17817 (2021)]: “Effects of Low-frequency Noise from Wind Turbines on Heart Rate Variability in Healthy Individuals.”
The Abstract follows:
Wind turbines generate low-frequency noise (LFN, 20–200 Hz), which poses health risks to nearby residents. This study aimed to assess heart rate variability (HRV) responses to LFN exposure and to evaluate the LFN exposure (dB, LAeq) inside households located near wind turbines.
Thirty subjects living within a 500 m radius of wind turbines were recruited. The field campaigns for LFN (LAeq) and HRV monitoring were carried out in July and December 2018. A generalized additive mixed model was employed to evaluate the relationship between HRV changes and LFN. The results suggested that the standard deviations of all the normal to normal R–R intervals were reduced significantly, by 3.39%, with a 95% CI = (0.15%, 6.52%) per 7.86 dB (LAeq) of LFN in the exposure range of 38.2–57.1 dB (LAeq).
The indoor LFN exposure (LAeq) ranged between 30.7 and 43.4 dB (LAeq) at a distance of 124–330 m from wind turbines. Moreover, households built with concrete and equipped with airtight windows showed the highest LFN difference of 13.7 dB between indoors and outdoors. In view of the adverse health impacts of LFN exposure, there should be regulations on the requisite distances of wind turbines from residential communities for health protection.
Introduction
Wind energy is used around the world as a source of clean energy. However, wind turbines generate low-frequency noise (LFN) in the range of 20–200 Hz. As many community complaints have centered around the LFN from wind turbines, it is important to evaluate the health impacts of LFN on residents near wind farms.
LFN exposure has been found to cause a variety of health conditions. Exposure to LFN from wind turbines results in headaches, difficulty concentrating, irritability, fatigue, dizziness, tinnitus, aural pain sleep disturbances, and annoyance. Clinically, exposure to LFN from wind turbines may cause increased risk of epilepsy, cardiovascular effects, and coronary artery disease.
It was also found that exposure to noise (including LFN) may have an impact on heart rate variability (HRV). HRV is the variation over time of the period between adjacent heartbeats, which is an indicator of the activities of the autonomic nervous system, consisting of the sympathetic nervous system (SNS) and parasympathetic nervous system (PNS). Autonomic imbalance usually represents a hyperactive SNS and a hypoactive PNS and results in reduced HRV.
An autonomic imbalance may increase the morbidity and mortality of cardiovascular diseases25. A review paper indicated that road traffic noise may overactivate the hypothalamic-pituitary-adrenocortical axis (HPA) and sympathetic-adrenal-medullar axis (SAM), increase the blood pressure and reduce HRV, and finally affect the cardiovascular system26. A recent study analyzing 658 measurements of HRV obtained from 10 healthy males (18–40 years old) indicated reductions in HRV due to environmental LFN exposure27. However, few studies have specifically examined the effect of LFN from wind turbines on HRV in healthy individuals; thus, this was the aim of this study.
In view of the adverse health impacts of noise exposure, many countries and international organizations have established regulations for noise control. These regulations are set for noise in the full spectrum of human hearing (20–20 k Hz). The Ministry of Environment of Finland set limits for wind farm noise of 45 dB (LAeq) during the day and 40 dB (LAeq) during the night.
In the United Kingdom, the fixed limit for turbine noise is 40 dB (LAeq) for the daytime and 43 dB (LAeq) for the nighttime. In the United States, noise levels of ≤ 55 dB (LAeq) are set for outdoors in residential areas, farms, and other outdoor areas as requisites for public health protection, and levels of 45 dB are set for indoor residential areas, hospitals, and schools.
In addition to the full noise spectrum, the Taiwan Environmental Protection Administration (EPA) also established regulations for LFN to avoid impacts on residents, since wind farms have been set up very close to residential communities. The LFN standards for wind turbines in the daytime (7 a.m.–7 p.m.) and evening (7 p.m.–10 p.m.) are 39 dB (LAeq) for environments requiring tranquility such as residential areas, 44 dB (LAeq) for mixed residential and commercial/industrial areas, and 47 dB (LAeq) for industrial areas; those at nighttime (10 p.m.–7 a.m.) are 36, 36, 41, and 44 dB (LAeq), respectively32. This study assessed the LFN in the indoor environments of households near wind turbines to evaluate whether the LFN levels meet the Taiwan EPA standards.
One of the most important factors influencing residential noise exposure from wind turbines is the distance of the wind turbine from the observer33. For example, at a distance of 120–500 m, the measured turbine noise levels decreased by 3–5 dB (LAeq), while at a distance of 1000 m the noise was reduced by 6–7 dB (LAeq). Hansen et al. reported variations in indoor LFN levels (15–45 dB (LAeq)) for two households (houses made of sandstone/concrete/iron or bricks with windows remaining closed or half open) at different distances from wind turbines.
This study assessed the indoor/outdoor differences in LFN exposure in several households located at varying distances from wind turbines. Our main focus was on the indoor LFN levels in several recruited households; we did not intend to conduct a comprehensive evaluation of the influential factors. These households serve the purpose of demonstrating the potential impacts of influential factors.
Besides distance from turbines, building materials also affect indoor LFN exposure. This work assessed the indoor LFN levels for several recruited households with different building materials and open/closed windows to illustrate their potential impacts. It is known that materials have different sound absorption coefficients.
The overall sound pressure level and spectrum of external noise change when transmitted to the interior of a building. Mid- and high-frequency noises are selectively attenuated by roofs and walls, causing the building structure to function like an LFN pass filter.
Outdoor to indoor noise reduction generally decreases with frequency, which is related to housing construction and room dimensions. Factors contributing to indoor/outdoor noise reduction also include structural resonances, room modes, and coupling between the air volume inside the residence and the stiffness of the walls, roofs, and ceilings. It is known that the appropriate choice of construction materials and designs can contribute to LFN exposure reduction for residents. Hence, these factors are not evaluated comprehensively in this study.
Taiwan is a small and highly populated island. Wind farms have been set up near residential communities, affecting the day-to-day lives of the residents. The hypothesis of this study is that LFN from wind turbines might affect HRV of residents. In order to verify the hypothesis of this study, we defined two objectives: to evaluate the LFN and HRV relationship with an intervention design and to assesses the actual LFN exposure of the community residents.
This investigation is the first in Asia examining the impact of LFN from wind turbines on the HRV of healthy residents. In addition, the variations in LFN exposure inside several residences constructed of different building materials are examined. The findings of this study would serve as a useful reference for Asian countries planning to launch or promote wind power generation.
It’s a simple lookup to learn that infrasound penetrates thru and into structures much more easily than higher frequencies. Closing windows isn’t going to help much if at all w/the lowest frequencies.
WIND TURBINE NOISE ADVERSELY IMPACTS NEARBY PEOPLE AND ANIMALS
https://www.windtaskforce.org/profiles/blogs/wind-turbine-noise-adversely-impacts-nearby-people-and-animals-1
Excerpt:
Europe and the US have been building onshore wind turbine plants in rural areas for more than 25 years. Anyone living within about 1.0 mile of such plants would experience the noises year-round, year after year. Those nearby people would be:
– Having decreasing property values.
– Having damage to their health, due to lack of sleep and peace of mind.
– Living with closed windows and doors, due to year-round noises.
– Having exposure to infrasound.
The wind turbine noise problem is worldwide. Due to a lack of worldwide guidelines, various political entities have been developing their own codes for the past 30 years. The World Health Organization is finally addressing the lack of detailed guidelines regarding such noises.
World Health Organization Noise Guidelines: WHO, publishes detailed guidelinesregarding various, everyday noises, such as near highways and airports, within urban communities and in work places. The guidelines serve as input to local noise codes.
In general, wind turbines are located in rural areas. When they had low rated outputs, say about 500 kW in the 1960s and 1970s, they made little audible noise, and the infrasound was weak. However, when rated outputs increased to 1000 kW or greater, the audible and infrasound noises became excessive and complaints were made by nearby people all over the world.
WHO, which has not published any detailed guidelines regarding wind turbine noises, will be releasing environmental noise guidelines for the European region in the near future.
Worldwide guidelines regarding wind turbine noises are needed to protect nearby rural people, such as regarding:
– The maximum outdoor dBA value, how that value is arrived at, such as by averaging over one hour, where that value is measured, such as near a residence, or at the resident property line to enable that resident to continue to enjoy his entire property.
– How to measure, or calculate the outdoor-to-indoor sound attenuation of a residence.
– How much setback is needed, such as one mile to minimize infrasound impacts on nearby residents.
– The maximum dB value of infrasound, how that value is arrived at, where that value is measured.
– How to determine the need for a 5 dB annoyance penalty.
The lack of such guidelines has resulted in various political jurisdictions creating their own codes. That process has been heavily influenced by well-financed, pro-wind interests, which aim to have the least possible regulation to maximize profits.
Comparison of Wind Turbine Codes: Below are some highlights from the noise codes of various political entities to illustrate their diversity:
1) DENMARK: Because Denmark was an early developer of wind turbine power plants, its noise code is more detailed than of most political entities. It has a buffer zone of 4 times total height of a wind turbine, about 4 x 500 = 2,000 ft, about 0.61 km (no exceptions), and it also has the following requirements regarding outdoor and indoor noise:
OUTDOOR
– For dwellings, summer cottages, etc.: 39 dBA (wind speeds of 8 m/s, 18 mph) and 37 dBA (wind speeds of 6 m/s, 13 mph)
– For dwellings in open country: 44 dBA (wind speeds of 8 m/s) and 42 dBA (wind speeds of 6 m/s)
The below regulations describe the methods and time periods over which sounds are to be measured:
– Page 4, par 5.1.1 mentions averaging over various periods. Only the worst average readings of a period are to be considered for compliance.
– Page 4, par 5.1.2 mentions a 5 dB annoyance penalty must be added to the worst average readings for a period for clearly audible tonal and impulse sounds with frequencies greater than 160 Hz, which would apply to wind turbine sounds.
– Page 6, par 5.4 mentions limits for indoor A-weighted low frequency noise 10 – 160 Hz, and G-weighted infrasound 5 – 20 Hz.
“If the perceived noise contains either clearly audible tones, or clearly audible impulses, a 5 dB annoyance penalty shall be added to the measured equivalent sound pressure level” That means, if a measured outdoor reading is 40 dBA (open country, wind speed 6 m/s), and annoyance is present, the reading is increased to 45 dBA, which would not be in compliance with the above-required 42 dBA limit.
In some cases, a proposed wind turbine plant would not be approved, because of the 5 dB annoyance penalties. The noise of wind turbines varies up and down. The annoyance conditions associated with wind turbines occur year-round. The annoyance conditions associated with other noise sources usually occur much less frequently.
NOTE: The 5 dB penalty does not apply to indoor and outdoor low frequency and infrasound noises, i.e., 160 Hz or less.