Infrasound Levels Research Articles

Dear Dr. Schweitzer, Thank you for your email. I believe that you should contact Ms. Borowa-Malinowska (PAN) as mentioned by Prof. Stolarski. We (PWN) are not the holders of the rights in the journal described below. Yours sincerely,Agnieszka Piotrowska-Strojna

The aim of the research was to determine the occurrence of possible, significant levels of infrasound and low frequency noise both in classrooms and around the primary school. Two sources of noise during research were significant: traffic on the national road and a wind farm, located near the school building. So far, few studies have been published regarding the impact of low-frequency, environmental noise from communication routes. The identification of hazards in a form of estimated noise levels resulted in preliminary information whether the location of the school near the road with significant traffic and the nearby wind farm can cause nuisance to children. There have been determined the criteria for assessing infrasound and low frequency noise. There have been made third octave band analyses of noise spectrum and the essential noise indicators were calculated. The results of learning in that school were thoroughly analysed for a long period of time and they were compared to the results obtained in other schools within a radius of 200 km situated near similar noise sources. Chosen assessment criteria show small exposure to low frequency noise. Measured infrasound noise levels are below hearing threshold.

Infrasound tones at sensation threshold level elicit measurable Frequency-Following responses

Even barely detectable levels of infrasound are often reported to cause annoyance and complaints. We carefully measured the individual sensation threshold of a pure tone and recorded immediately after the brain's frequency-following response (FFR) at this intensity using the same stimulator. In contrast to 87-Hz tones, 8-Hz tones elicit an FFR already at sensation threshold. Control stimuli with trains of 1-kHz tone pips having the repetition rate of the infrasound tone frequency and sensation threshold intensities evoked no significant FFR. Thus, slow periodicity, causing synchronous activation of auditory nuclei, is not explaining the FFR to low-level infrasound alone.

ACTUAL DIRECTIONS FOR THE IMPROVEMENT OF STATE BUILDING STANDARDS FOR THE DESIGN OF NEW AND RECONSTRUCTION OF EXISTING EDUCATIONAL INSTITUTIONS

The article provides an analysis of state building regulations that apply to the design of new and reconstruction of existing buildings of educational institutions, from the point of view of compliance with modern international requirements. The expediency of improving the state building regulations by supplementing them with the current requirements of European safety standards and standardizing the physical factors of the production environment has been demonstrated. It is shown that the requirements of individual national sanitary norms and rules, which are integral components of the considered state building norms, require coordination. Quantitative maximum allowable values of electromagnetic fields of individual frequency divisions, as well as approaches to determining integral indicators of electromagnetic load on the environment, require coordination. Organization of grounding and suppression of industrial frequency harmonics and interharmonics of electrical consumers with non-linear volt-ampere characteristics must be carried out at the stage of designing power supply systems for civilian buildings by improving the regulatory framework. Sanitary regulations and rules referred to by state building regulations must meet the requirements for the limit levels of infrasound and aeroionization of air, which should be implemented in view of the requirements of current European regulations.

Infrasound of a wind turbine reanalyzed as power spectrum and power spectral density

The infrasound levels due to the blade-tower interaction generated by a wind turbine in the publication by Pilger and Ceranna (JSV, Vol. 388, pp. 188–200, 2017) have to be corrected to be interpreted as sound pressure level. Also, the electrical power of the wind turbine should be corrected for the high wind case to 660 kW. We provide a reanalysis of the measured data with a power spectrum showing levels for the low-frequency signal of the wind turbine about 34 dB below the original work. All measured levels at a distance of 200 m from the wind turbine's infrasound signal are well below the hearing threshold.

Annoyance, perception, and physiological effects of wind turbine infrasound.

Even though some individuals subjectively associate various symptoms with infrasound, there are very few systematic studies on the contribution of infrasound to the perception, annoyance, and physiological reactions elicited by wind turbine sound. In this study, sound samples were selected among long-term measurement data from wind power plant and residential areas, both indoors and outdoors, and used in laboratory experiments. In the experiments, the detectability and annoyance of both inaudible and audible characteristics of wind turbine noise were determined, as well as autonomic nervous system responses: heart rate, heart rate variability, and skin conductance response. The participants were divided into two groups based on whether they reported experiencing wind turbine infrasound related symptoms or not. The participants did not detect infrasonic contents of wind turbine noise. The presence of infrasound had no influence on the reported annoyance nor the measured autonomic nervous system responses. No differences were observed between the two groups. These findings suggest that the levels of infrasound in the current study did not affect perception and annoyance or autonomic nervous system responses, even though the experimental conditions corresponded acoustically to real wind power plant areas.

МЕТОДЫ И РЕЗУЛЬТАТЫ ЭКОЛОГИЧЕСКОГО МОНИТОРИНГА НЕКОТОРЫХ ФИЗИЧЕСКИХ ЗАГРЯЗНЕНИЙ ОКРУЖАЮЩЕЙ СРЕДЫ НА ПРИМЕРЕ ТЕРРИТОРИИ ГОРОДСКИХ ОКРУГОВ САМАРСКОЙ ОБЛАСТИ

The paper is devoted to the problem of ecological monitoring of physical pollutions of environment of urban territories on the example of the territory of city districts of Samara region. Methods of carrying out of researches of physical pollutions are considered. In framework of researches measurements of levels of physical pollutions were carried out: ambient dose equivalent power of gamma radiation, external sources of variable electromagnetic fields of industrial (electrical and magnetic components) and radio frequency range (electrical and magnetic components and energy low density), sound and infrasound levels (equivalent, octave and third octave). Zones of the territory of Samara region with increasing of admissible levels were determined. In total results of researches and it comparison with results of previous measurements of physical pollutions on the territory of Samara region are showing that the level of negative impact of physical pollutions is increasing.

Negative effect of high-level infrasound on human myocardial contractility: In-vitro controlled experiment.

Background:Human exposure to infrasound is increasing due to man-made factors, such as occupational conditions, wind farms and transportation. The concern among the public regarding the safety of infrasound exposure is growing.Aims:To evaluate whether exposure to infrasound interferes directly with human cardiac function and contributes to pathological processes.Setting:The University Hospital of Mainz, Germany.Methods:Human myocardial tissues, obtained from patients undergoing cardiac surgery, were prepared in small muscle samples and stimulated electrically in-vitro for a period of almost two hours under physiological conditions to induce continuous pulsatile contractions and simulating a working human heart. Two samples were obtained from each donor: one was subjected to infrasound for 60 min and the other served as a control. Their contraction forces (CF) and durations (CD) were measured before and after each testing period and their relative changes (CF% and CD%) were calculated and introduced in a multilinear regression model. The following three infrasound levels of exposure were used in this study: 100, 110 and 120 dBz.Results:The measured CF% corresponded negatively with the infrasound level measured in dBz (R2 = 0.631; P = 0.018). The decrease measured almost −11% at 110 dBz and −18% at 120 dBz, after correction for control. The CD on the other hand remained unchanged.Conclusions:Exposure to high levels of infrasound (more than 100 dBz) interferes with cardiac muscle contractile ability, as early as one hour after exposure. There are numerous additional studies which support this conclusion. These results should be taken into account when considering environmental regulations.

Forecast Estimates Based on the Results of Measuring Infrasound in Residential Areas of the City of Saint Petersburg

Introduction. The process of predicting infrasound exposures in residential areas is difficult due to the lack of methods of mathematical modeling and calculating probable infrasound levels in an open area. The assessment of infrasound exposures in residential areas can be only performed using direct instrumental studies. The purpose of the study was to determine the prospects for organizing and monitoring infrasound exposures in residential areas. Materials and methods. We analyzed federal and departmental regulations on infrasound measurements. Low-frequency noise pollution in residential areas of various parts of St. Petersburg was studied. The objects of experimental research were selected in the immediate vicinity of road junctions, railways, air transport trajectories, and in the zones of large industrial enterprises. Results. More than 1,000 instrumental measurements were taken. We analyzed infrasound test reports, which were part of environmental engineering surveys, over a 10-year period and found significant discrepancies between the results obtained under similar conditions by various laboratories. Conclusions. We established that the infrasound levels produced by the main anthropogenic sources in St. Petersburg did not exceed permissible levels. We also substantiated inexpediency of conducting comprehensive studies and monitoring the parameters of infrasound in residential areas.

К ВОПРОСУ О СНИЖЕНИИ НЕГАТИВНОГО ВОЗДЕЙСТВИЯ ИНФРАЗВУКОВОГО ИЗЛУЧЕНИЯ В УСЛОВИЯХ УРБАНИЗИРОВАННЫХ ТЕРРИТОРИЙ НА ПРИМЕРЕ САМАРСКОЙ ОБЛАСТИ

The questions of reduction of negative impact of infrasound in conditions of urban territories on the example of Samara region are considered. General classification of methods of protection from infrasound impact is suggested. On the basis of analysis of sources and of results of measurements of infrasound levels in conditions of urban territories of Samara region suggestions for reduction of infrasound impact in the most dangerous zones of Samara region were developed.

Community-based infrasound investigation

Infrasound is not only associated with wind turbines and volcanoes. Low levels of disturbing infrasound that can have long term adverse impact on residents are also associated with sources such as bridges, transportation, barges, mechanical equipment and entertainment sound systems. This paper describes measurements to identify potential infrasound sources impacting a residence in a Mississippi River town in Minnesota. Initial monitoring was performed in a second floor room over a 24 h period with five samples up to 30 min using an Apollo sound analyzer. Supplemented with sound level meter readings, an average peak at 12.5 Hz appears to be associated with a nearby river crossing bridge. Peaks at this frequency peaks can not be attributed to room dimensions. Subsequent readings were taken in several rooms and outside with a micro-barometer system. These data supported earlier readings but showed differences between rooms and indoor and outdoor spectra. Unfortunately there are no standards or guidelines for indoor infrasound levels and only limited solutions for addressing these community infrasound sources. Whether or how infrasound could be incorporated into community noise ordinances that could possibly prevent adverse residential exposure to infrasound will be discussed.

Measurement and characterization of infrasound from a tornado producing storm.

A hail-producing supercell on 11 May 2017 produced a small tornado near Perkins, Oklahoma (35.97, -97.04) at 2013 UTC. Two infrasound microphones with a 59-m separation and a regional Doppler radar station were located 18.7 and 70 km from the tornado, respectively. Elevated infrasound levels were observed starting 7 min before the verified tornado. Infrasound data below ∼5 Hz was contaminated with wind noise, but in the 5-50 Hz band the infrasound was independent of wind speed with a bearing angle that was consistent with the movement of the storm core that produced the tornado. During the tornado, a 75 dB peak formed at ∼8.3 Hz, which was 18 dB above pre-tornado levels. This fundamental frequency had overtones (18, 29, 36, and 44 Hz) that were linearly related to mode number. Analysis of a larger period of time associated with two infrasound bursts (the tornado occurred during the first event) shows that the spectral peaks from the tornado were present from 4 min before to 40 min after tornadogenesis. This suggests that the same geophysical process(es) was active during this entire window.

Comparison of infrasound emissions observed during a tornado with potential fluid mechanisms

Infrasound may be emitted by tornado-producing storms up to 2 h before tornadogenesis, and due to their low atmospheric attenuation, these low frequencies may be detected several hundreds of kilometers away. Therefore, passive infrasound monitoring shows potential for the study and prediction of tornadoes, provided received infrasound signals can be correlated with the flow-fields of tornadoes. Literature indicates that tornadoes do cause high infrasound levels between 0.5 Hz and 10 Hz, but the radially vibrating vortex mechanism commonly proposed to explain this production [Abdullah, Mon. Weather Rev. 94, 213–220] has been shown to be non-physical. Schecter [Mon. Weather Rev. 140, 2080–2089] showed these limitations and showed using numerical experiments of a tornado-like vortex produced infrasound from around the storm’s melting level. As this level contains diabatic processes involving hail, it also appears that hail production could be connected to tornado infrasound. In the current work, observations of atmospheric infrasound during a small tornado that occurred on 11 May 2017, will be evaluated in light of these previous studies.

The main directions of prevention of noise pathology in the Armed Forces

In accordance with the existing Federal sanitary standards, noise and infrasound are considered to be an harmful production factor and in terms of their prevalence they occupy a leading place in the national economy. To prevent the harmful effects of noise and infrasound on the health of members of the armed forces establishes the main lines. For prognostic assessment of harmful influence of production factors on production facilities and transport the special assessment of working conditions is carried out without fail. Hygienic research of workplaces has shown that noise and infra-sound levels correspond to harmful and dangerous classes, that is, risks of professional pathology of acoustic Genesis are created. The presence of acoustic sources in the Armed forces requires constant monitoring of them, the annual special assessment of working conditions development of preventive measures. The impact of noise and infra-sound leads to a decrease in military and professional performance and an increase in General and professional morbidity. The leading place in the structure of morbidity of noise etiology is a sensorineural hearing loss. This requires further improvement of the provision of specialized assistance to military personnel in the presence of noise hearing loss. In the current regulations of the military medical services noise and infrasound are not identified as a harmful factor, and therefore not fully developed the issues of professional selection, monitoring and medical examination of noise pathology. An important place in the system of prevention of harmful effects of noise is given to the means especially individual of protection against noise. Their absence and low efficiency pose a threat to the acoustic safety of military personnel. Provision of personnel with means of individual protection against noise and control of the correctness of their operation are the most relevant measures to reduce the noise pathology of the hearing organ. The existing system of measures to combat the harmful effects of noise in the Armed forces requires revision in accordance with the existing state legislative and legal framework.

Amplitude Modulation May Be Confused with Infrasound

Environmental infrasound is usually accompanied by low-frequency (LF) sounds. Considering that inner hair cell transduction equals half-wave rectification, activity of low-frequency auditory nerve fibres may be indistinguishable whether elicited by LF sound that is amplitude-modulated at an infrasonic rate, or LF sound that is superimposed onto infrasound that biases the basilar membrane position. We tested whether listeners are able to distinguish a 63-Hz carrier tone, amplitude modulated at 8 Hz, from a 63-Hz pure tone that was perceptually loudness-modulated by an 8-Hz biasing tone. Using a maximum-likelihood procedure, 12 participants first adjusted the intensity of the 8-Hz tone so that the perceived modulation of the pure tone matched a reference amplitude-modulated tone. Both stimuli types were then presented in random order, and participants had to identify presentations which contained the infrasound tone. About half the participants performed close to chance. The best had 81% correct. Experiments with a 125-Hz carrier tone gave similar results. Although performance may improve in a 2-interval discrimination task, this would not be representative of real listening conditions. Results suggest that slowly amplitude-modulated LF sounds may underlie complaints about environmental infrasound, where measured infrasound levels are well below sensation threshold.

Wind turbine low frequency and infrasound propagation and sound pressure level calculations at dwellings.

This study was developed to estimate wind turbine low frequency and infrasound levels at 1238 dwellings in Health Canada's Community Noise and Health Study. In field measurements, spectral peaks were identifiable for distances up to 10 km away from wind turbines at frequencies from 0.5 to 70 Hz. These measurements, combined with onsite meteorology, were in agreement with calculations using Parabolic Equation (PE) and Fast Field Program (FFP). Since onsite meteorology was not available for the Health Canada study, PE and FFP calculations used Harmonoise weather classes and field measurements of wind turbine infrasound to estimate yearly averaged sound pressure levels. For comparison, infrasound propagation was also estimated using ISO 9613-2 (1996) calculations for 63 Hz. In the Health Canada study, to a distance of 4.5 km, long term average FFP calculations were highly correlated with the ISO based calculations. This suggests that ISO 9613-2 (1996) could be an effective screening method. Both measurements and FFP calculations showed that beyond 1 km, ISO based calculations could underestimate sound pressure levels. FFP calculations would be recommended for large distances, when there are large numbers of wind turbines, or when investigating specific meteorological classes.

Scaling of a gas-combustion infrasound source

For equal storage pressure, the available energy density from propane-air combustion is substantially higher than the available energy density from expansion of a compressed gas. Ordinary liquid propane is stored at a pressure of about 1 MPa (150 psi). The potential-energy density in air that has been compressed to 1 MPa is about 170 kJ/kg; the combustion-energy density in propane is about 50 000 kJ/kg. In addition, there is a substantial volumetric advantage to propane in that it condenses to a liquid under normal storage pressures. Given the successful demonstration of compressed-gas infrasound sources (Barlett et al., J. Acoust. Soc. Am. 141, 3567, 2017), useful levels of infrasound might also be produced by cycling a burner on and off. Previous work (Smith and Gabrielson, J. Acoust. Soc. Am. 137, 2407, 2015) with a 90 kW propane burner demonstrated the potential for generating infrasound by periodic thermal expansion of the surrounding air and the levels measured were supported by a simple thermodynam...

The Study on Vibroacoustic Characteristics of Shunting Locomotive Cabin

Power plant of shunting locomotive is a powerful source of infrasound. If the level of infrasound is more than 100dB, the time of operator work should be limited. The paper presents a simultaneous measurement of infrasound and low-frequency vibration at various modes and loads. The levels of infrasound and low-frequency vibration were measured inside the cabin and near the shunting locomotive. It was detected that infrasound depends on low-frequency vibration. There was a relationship between the level of infrasound and the opened window inside the cabin. Some recommendations to reduce the infrasound level were developed. The results indicate, overall, that the level of infrasound exceeds the standard values. The implementation of developed recommendation could reduce the level of infrasound.

Measurements of infrasound blade pass frequencies inside multiple homes using narrowband analysis

Previous measurements in homes near wind turbines indicate higher pressure levels below 10Hz than audible pressure levels measured at the same time and location (Dooley and Metelka, ASA 20, 2013). Long term measurements of Infrasound pressures appear inside multiple homes as wind speed and wind direction vary. Measuring Narrowband signatures identify fingerprints of rotational components of wind turbines. The measurements directly correlate how blade pass frequencies appear and disappear everywhere as wind changes. Data from four homes were measured and broadband infrasound levels from wind are compared to tonal infrasound blade pass frequencies In both cases, broadband infrasound and blade-to-tower pressures increase with wind and advanced signal processing techniques were used tracking signatures buried in noise.

Theoretical model and experimental validation of a gas- combustion infrasound source

The design of controlled infrasound sources is challenging due to the large volumes of air that must be moved with a source of practical size. One possible approach is to produce a periodic volume expansion/contraction by periodic heating of the air mass using a combustible-gas burner. For equal storage pressure, the available energy density from combustion of a gas is substantially higher than the available energy density from expansion of a compressed gas. While no source that is much smaller than a wavelength will be anything but inefficient, this large energy density may partially offset this basic acoustical inefficiency making gas-combustion infrasound source technology practical for use in the field. The goal of this work is to generate usable levels of sound in the 0.1 to 20 Hz frequency band for infrasound-measurement-system calibrations and propagation-path characterization. This paper presents a theoretical model and experimental demonstration of this infrasound generation method. Both theory and demonstration suggest that usable infrasound levels can be generated with a relatively compact source.

Health-based audible noise guidelines account for infrasound and low-frequency noise produced by wind turbines.

Setbacks for wind turbines have been established in many jurisdictions to address potential health concerns associated with audible noise. However, in recent years, it has been suggested that infrasound (IS) and low-frequency noise (LFN) could be responsible for the onset of adverse health effects self-reported by some individuals living in proximity to wind turbines, even when audible noise limits are met. The purpose of this paper was to investigate whether current audible noise-based guidelines for wind turbines account for the protection of human health, given the levels of IS and LFN typically produced by wind turbines. New field measurements of indoor IS and outdoor LFN at locations between 400 and 900 m from the nearest turbine, which were previously underrepresented in the scientific literature, are reported and put into context with existing published works. Our analysis showed that indoor IS levels were below auditory threshold levels while LFN levels at distances >500 m were similar to background LFN levels. A clear contribution to LFN due to wind turbine operation (i.e., measured with turbines on in comparison to with turbines off) was noted at a distance of 480 m. However, this corresponded to an increase in overall audible sound measures as reported in dB(A), supporting the hypothesis that controlling audible sound produced by normally operating wind turbines will also control for LFN. Overall, the available data from this and other studies suggest that health-based audible noise wind turbine siting guidelines provide an effective means to evaluate, monitor, and protect potential receptors from audible noise as well as IS and LFN.