Daily fluctuations in aircraft noise exposure around civil airports and military airfields in Japan

In Japan, yearly average of (day-evening-night sound level) as cumulative noise index has been adopted in national noise guideline of "Environmental Quality Standards for Aircraft Noise." Daily flight movements at civil airports are almost stable because of scheduled airline flight. On the other, daily total flight movements at military airfields greatly change day to day because of training flights, etc. Thus, noise exposure around the airport may change significantly from day to day due to change of flight movement. This paper shows examples of fluctuations, frequency distribution and deviation of daily using aircraft noise monitoring data around civil airports and military airfields. In the case of civil airports, standard deviation of daily was less than 5 dB at the monitoring stations where the yearly average of were about 55 dB or more. However, the standard deviation of daily increased 10 dB or more in some cases at points where yearly average of less than 55 dB. Furthermore, in the case of military airfields, the standard deviation of daily were 5 dB or more for all monitoring stations.