Loudness-level weighting for environmental noise assessment

摘要

Assessment of combined noise environments has been the subject of much research and debate. There is a need to assess the urban/suburban noise environment using a single, all-encompassing method. Currently, most countries use some form of the A-weighted equivalent level (ALEQ) to assess most noises. Many adjustments have been suggested to provide a method whereby all noise can be assessed using ALEQ. But overall, the A-weighting method works pretty well. The question is: Is there some incremental improvement that can be made to ALEQ that will better reduce some its known deficiencies ? A-weighting only operates in the frequency domain. It provides a constant filter that is independent of sound level. In this paper, we suggest the use of the equal loudness-level contours (ISO 226, 1987) as a dynamic filter that changes with both sound level and frequency. It is shown that loudness-level-weighted sound exposure level (LLSEL) and loudness-level-weighted equivalent level (LL-LEQ) can be used to assess environmental noise. Compared with A-weighting, loudness level weighting better orders and assesses transportation noise sources, and it better assesses sounds with strong, low-frequency content. Also, with the addition of a 12-dB adjustment, loudness-level weighting better orders and assesses highly impulsive sounds. [References: 31]