Assessment of the health effects of low-frequency sounds and infra-sounds from wind farms
Résumé
The French Agency for Food, Environmental and Occupational Health and Safety (ANSES) reiterates that wind turbines emit infra-sounds (sound below 20 Hz) and low-frequency sounds. There are also other sources of infra-sound emissions that can be natural (wind in particular) or anthropogenic (heavy-goods vehicles, heat pumps, etc.). The measurement campaigns undertaken during the expert appraisal enabled these emissions from three wind farms to be characterised. In general, only very high intensities of infra-sound can be heard or perceived by humans. At the minimum distance (of 500 metres) separating homes from wind farm sites set out by the regulations, the infra-sounds produced by wind turbines do not exceed hearing thresholds. Therefore, the disturbance related to audible noise potentially felt by people around wind farms mainly relates to frequencies above 50 Hz. The expert appraisal showed that mechanisms for health effects grouped under the term 'vibro-acoustic disease', reported in certain publications, have no serious scientific basis. There have been very few scientific studies on the potential health effects of infra-sounds and low frequencies produced by wind turbines. The review of these experimental and epidemiological data did not find any adequate scientific arguments for the occurrence of health effects related to exposure to noise from wind turbines, other than disturbance related to audible noise and a nocebo effect, which can help explain the occurrence of stress-related symptoms experienced by residents living near wind farms. However, recently acquired knowledge on the physiology of the cochlea-vestibular system has revealed physiological effects in animals induced by exposure to high-intensity infra-sounds. These effects, while plausible in humans, have yet to be demonstrated for exposure to levels comparable to those observed in residents living near wind farms. Moreover, the connection between these physiological effects and the occurrence of a health effect has not been documented. In this context, ANSES recommends: Concerning studies and research: - verifying whether or not there is a possible mechanism modulating the perception of audible sound at intensities of infra-sound similar to those measured from local residents; - studying the effects of the amplitude modulation of the acoustic signal on the noise-related disturbance felt; - studying the assumption that cochlea-vestibular effects may be responsible for pathophysiological effects; - undertaking a survey of residents living near wind farms enabling the identification of an objective signature of a physiological effect. Concerning information for local residents and the monitoring of noise levels: - enhancing information for local residents during the construction of wind farms and participation in public inquiries undertaken in rural areas; - systematically measuring the noise emissions of wind turbines before and after they are brought into service; - setting up, especially in the event of controversy, continuous noise measurement systems around wind farms (based on experience at airports, for example). Lastly, the Agency reiterates that the current regulations state that the distance between a wind turbine and the first home should be evaluated on a case-by-case basis, taking the conditions of wind farms into account. This distance, of at least 500 metres, may be increased further to the results of an impact assessment, in order to comply with the limit values for noise exposure. Current knowledge of the potential health effects of exposure to infra-sounds and low-frequency noise provides no justification for changing the current limit values or for extending the spectrum of noise currently taken into consideration
Mots clés
BIOLOGICAL EFFECTS
CHRONIC EXPOSURE
ENERGY SOURCE DEVELOPMENT
ENVIRONMENTAL EXPOSURE
ENVIRONMENTAL IMPACTS
EPIDEMIOLOGY
HZ RANGE
MODULATION
NOISE POLLUTION
POLLUTION REGULATIONS
PUBLIC ANXIETY
PUBLIC HEALTH
PUBLIC INFORMATION
PUBLIC OPINION
RECOMMENDATIONS
RISK ASSESSMENT
SOCIO-ECONOMIC FACTORS
WIND TURBINE ARRAYS
FREQUENCY RANGE
INFORMATION
INSTITUTIONAL FACTORS
LAWS
POLLUTION
REGULATIONS
