AIrport Noise - Integrating Total Annoyance by the Use of an Exchange Rate Concept

Consultant in Acoustics and Noise ControlIt is well established that comunity response to noise from aircraft in flight varies widely, and most studies have shown that if individual people's responses are rated on a numerical scale of annoyance scores, the distribution is gener ally Gaussian (1,2,3).For the purposes of providing a basis for political decisions, it is connnon practice to calculate a single quantity such as the average annoyance score for a range of values of the aircraft noise index in order to simplify the issues before the decision makers.For example, in public inquiries, it has become virtually standard practice to say that 55 NIH is 'low annoyance'; 45 NM is 'moderate annoyance' and 55 NNI is 'high annoyance'.However, simplifications such as these are made without any real justification.For instance, in arriving at an average annoyance score, a commonly used method involves multiplying the number of people in each cell by the numerical value of the annoyance score (on a scale from 0 to 6), summing the results and divid ing them by the total number of people.This presupposes that a person respond ing with an annoyance score of, say, 6 is equal to six people each with an annoyance score of 1.No attempt is made to justify this 'exchange rate'.