Potential quiet areas in Europe, based upon Quietness Suitability Index (QSI) and Natura 2000 protected areas

Suitable distance layer from noise sources built following a fuzzy approach (*), calculating the 'membership' to the quietness range (0–1) by means of a linear relationship, considering the mean value obtained as no suitable (= 0) and maximum distance obtained as suitable (= 1). The distance values between not suitable (mean value) and suitable (maximum value) will be reassigned with a new value between 0 and 1 following a linear equation. The noise map has been combined with the Natura 2000 data for Europe.

 (*) The production of threshold distance layers around noise sources has been made following a fuzzy approach rather than obtaining a buffer with sharp limits. Membership to a 0-1 range has been obtained according to a linear function.