Time-of-day corrections in measures of aircraft noise exposure

Results of a socio-acoustic study of human reaction to aircraft noise around Australian airports are described. The relative importance of night, evening, and daytime operations in determining overall reaction is assessed using a correlation analysis procedure. The results indicate that night-time weightings used in most existing noise exposure indices including NEF and DNL, are too large. However, other evidence suggests that both night and evening weightings should be greater than 0 dB. The optimal weightings found were about 3 dB for night-time operations and 9 dB for evening operations. However, other considerations indicate that in a practical noise index it may be more reasonable to apply a weighting of about 6 dB during both night and evening hours.