How to measure community tolerance levels for noise.

Area of Science:

• Environmental acoustics
• Psychoacoustics
• Transportation noise research

Background:

• Aircraft noise annoyance is primarily linked to the day-night average sound level (DNL).
• Non-DNL factors significantly influence noise annoyance but are complex to model.
• The community tolerance level (CTL) was introduced to aggregate these non-DNL influences.

Purpose of the Study:

• To investigate and compare different methods for measuring the community tolerance level (CTL).
• To evaluate the uncertainty associated with CTL measurement methods.
• To recommend a superior method for CTL assessment in noise annoyance studies.

Main Methods:

• Analysis of existing literature data on noise annoyance.
• Surveys conducted around two Norwegian airports.
• Utilized simulated data for method validation.
• Compared an elementary measurement method against the least-squares method.

Main Results:

• Significant differences were observed between the results of various CTL measurement methods.
• The elementary method demonstrated a smaller measurement uncertainty compared to the least-squares method.
• Methods for evaluating measurement uncertainty were successfully presented and applied.

Conclusions:

• The elementary method is recommended as a more reliable and precise replacement for the original least-squares method for CTL measurement.
• Accurate CTL measurement is crucial for better modeling of transportation noise-induced annoyance.
• Further research into uncertainty evaluation methods for CTL is warranted.