Records of aircraft noise exposure and its secular change around the Kadena airfield in Okinawa

概要

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Okinawa has for geographical and historical reasons 75% of U.S. bases and facilities in Japan. Chronic aircraft noise exposure around Kadena Air Base and Futenma Air Station situated in the midst of cities causes serious disturbance to local residents. About 480,000 people corresponding to 38% of the prefectural population reside in the area where aircraft noise exposure exceeds the environmental standard set by the Environment Agency of Japan. This report shows the past noise measurements and estimated noise exposure level around the Kadena airfield. During the Vietnam War, the estimation of noise exposure based on the record tells WECPNL was around 105 which is by 5 to 15 higher than the WECPNL the Defense Facilities Administration Agency (DFAA) now designates, and L_<Aeq,24h> came up to 85 dB. The maximum sound level recorded in 1972 was 127dB in front of a residence in Kadena Town while engine tuning was carried out. The noise exposure gradually decreased at some monitoring points after 1986 because of the installation of silencers and the change of flight manoeuvres but has been basically the same for the past 20 years under the flight paths.
社団法人日本音響学会の論文