MONITORING AND ANALYSIS OF AIRPORT NOISE.

The noise monitoring system at the two national airports near Washington, D. C. , is providing valuable informaton on noise conditions around those two airports. Beyond merely documenting the actual noise levels there, the system provides detailed analyses of the make-up of the noise, the contribution of aircraft to the overall noise picture, the identification of deviant noise sources, and the long-term trends. The system also provides valuable research information, permitting the FAA to verify mathematical and computer calculations of noise impacts by direct comparison with measured data, and to determine more accurate attenuation factors for aircraft noise.