Following preliminary research for a major aircraft manufacturer, Hayes McKenzie carried out further and more definitive research in association with the Institute of Sound & Vibration Research, at the University of Southampton, on tonal content of aircraft noise. Essentially, the research shows that the characteristic 'buzz saw' noise, exhibited by some modern jet aircraft on take-off, is not picked up as 'tonal' by the measures which have been used for quantification and certification of aircraft noise since the 1960s. Alternative methods are proposed in the paper as a first step towards correcting this.
The long-awaited latest guidance from the World Health Organization was released yesterday (10th October 2018). Of particular interest to Hayes McKenzie is the section specifically concerned with wind turbine noise. A quick flip to Section 34 on page 77 reveals that the WHO are conditionally recommending that turbine noise should not exceed an Lden of 45dB. Lden is the average noise level over one year, where noise during the evening is penalised with a +5 dB correction, and a +10dB correction applied for noise at night. In the case of wind turbine noise, which is continually varying from day to day, depending on the wind speed and direction, it will be almost impossible to establish compliance with this limit through measurement alone. As a means of 'impact' assessment, however, it has some distinct advantages which are discussed in Andy McKenzie's paper for Acoustics Australia in 2012 and in a paper presented at the Institute of Acoustics Autumn Conference in 2015 by Andy along with fellow wind turbine noise specialist Andrew Bullmore. Both of these papers are available in the Publications - Our Published Papers section of this web site.
The new (2018) NPPF refers to noise at Paragraph 170(e) where it states that:
Planning policies and decisions shoud contribute to and enhance the natural and local environment by preventing new and existing development from contributing to, being put at unacceptable risk from, or being adversely affected by, unacceptable levels of soil, air, water or noise pollution or land instability.
It is considered further in general terms at Paragraph 180 and for minerals extraction at Paragraphs 204 and 205.
There was much discussion among interested parties following the publication of a report for the UK Government which recommended a 'penalty scheme' for regulating AM but little information on how to use it. This paper, presented by Malcolm and others, discusses different factors which require additional consideration when considering a potential penalty to be used in combination with the IoA AM noise working group method for quantifying AM.