Validity of the method of estimating long-term average cumulative aircraft noise exposure based on repetitive short-term noise measurements

This paper discusses the validity of methods of estimating long-term average cumulative aircraft noise exposure, measured in Lden, around the airport. Last year, Ministry of the Environment, Japanese Government, notified a revised guideline of "Environmental Quality Standard for aircraft noise," in which noise index for evaluating aircraft noise was changed from WECPNL to Lden. Now, in the guideline, it is requested to estimate annual average cumulative noise exposure around the airport, being based on repetitive short-term noise measurements, but the validity has not been examined up to now. Thus, taking this opportunity, we investigated whether it is valid to estimate annual average cumulative noise exposure at various sites around airports using results of repetitive short-term noise measurements. First, this presentation gives a brief summary of the revision of the standard. Secondly, it discusses the variability in the estimations of long-term average cumulative noise exposure calculated from repetitive short-term noise measurements with regards to the measurement time period. It was confirmed that in case of civil airports power average of one-week measurements repeated seasonally twice or four times a year makes it possible to get a good estimation of annual average cumulative noise exposure. Finally, it also discusses effective ways we estimate single event noise exposure, measured in sound exposure level or maximum sound pressure level, under various environmental noise situations around airports.