Exposure of Communities to Low‐Frequency Noise from Aircrafts and Rockets

Data collections, in the low‐frequency noise region (below 100 cps), in communities located near airports were analyzed for the purpose of volumetric coverage. The following factors, such as residential areas under influence, volume of noise, time of noise, and range of influence, have indicated the importance of these studies. Isosurfaces of SPL of jet planes at altitudes of up to 7000 ft are shells in the shape of pears, with the top directed towards the ground. The top covers a minimum area of 12 000 km2. The pearshaped envelope is pulled in the direction of the flight, and this produces a time delay and altitude dependence between the community exposure to radiated noise, and the instantaneous location of the plane. Typical time exposures for altitudes of 1000 to 7000 ft are 45–74 sec. This low frequency does not raise complaints because of the human ear's limitations; nevertheless they might be harmful. Furthermore, infrasonic frequencies (4 cps and below), having energies of 100 dB and more, cover 1...