SHOULD LIMIT VALUES BE SET FOR INFRASOUND CAUSED BY WIND TURBINES?

TL;DR

This study proposes outdoor exposure limits for wind turbine infrasound to prevent annoyance and health effects.

Contribution

The study introduces a G96 curve-based method to set preliminary infrasound exposure limits for wind turbines.

Findings

Infrasound levels around wind farms are below the hearing threshold and not harmful.

Proposed limits include 90 dB for daytime and LDEN(G), and 85 dB for nighttime indices.

Abstract

The study focuses on setting outdoor exposure limits for wind turbine infrasound, as most countries currently have no specific limits for this type of noise. A review of the literature on the effects of wind turbine infrasound and the methods used worldwide to measure and assess environmental exposure to infrasound formed the basis for setting limits. According to the literature, human tolerance to infrasound is defined by the hearing threshold, which is not yet standardized. Therefore, a G96 curve (corresponding to tones with the G-weighted sound pressure level (SPL) equal to 96 dB) was used to determine the mean hearing threshold in the 1–20 Hz frequency range. Infrasound that cannot be heard (or felt) is not annoying and does not cause other adverse health effects. The infrasound levels measured around wind farms are well below the hearing threshold. Few countries have set limits for infrasound in either outdoor or indoor environments. The study proposes the G-weighted equivalent SPL as the basis for assessing exposure to infrasound from wind turbines. It also specifies preliminary short-term indices (i.e., G-weighted equivalent SPLs for daytime [LGeq, D] and nighttime [LGeq, N]) and long-term indices (i.e., averaged G-weighted day-evening-night infrasound level [LDEN(G)] and G-weighted night infrasound level [LN(G)]). In order to avoid annoyance and other possible harmful effects, regardless of land use, 90 dB was provisionally adopted as an acceptable value for LGeq, D and LDEN(G), and 85 dB for LGeq, N and LN(G). The study highlights the importance of considering specific exposure limits for wind turbine infrasound to ensure the well-being and comfort of people living near wind turbines.

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