Airport zoning based on a logical condition on LAeqD and LAeqN noise metrics
Résumé
In the Resolution A33 / 7, 2001, ICAO has presented a balanced approach related the problem of airport noise control. In this approach the four aspects considered are: Reduction at source of aircraft noise, planning and land management, operational procedures for reducing noise and operational restrictions. The one that presents more difficulties in implementation is management of land use in the case of Brazil. The urban zoning aims to ensure the comfort of the population, divide the city into zones and for each zone set a noise criterion level at daytime and at nighttime. The metric used in urban zoning is the equivalent sound level. The metric used for the airport zoning is DNL which is 24h metrics and is directly related with annoyance. The use of the DNL metric in airport noise zoning is based in the works of Schultz that were later improved by Fidel. The inconsistencies between metrics create urban conflicts due to lack of communication and understanding of the zoning approach used. The analysis has shown that the DNL metric has problems to zoning airports with restrictions on nighttime use. In urban zoning it is recommended to use the equivalent sound level LAEQ, which uses different criteria to day and night periods to define the land use. It is possible, through a simple equation, to determine the DNL level associated to a LAeqD, LAeqN pair. The inverse problem, however, has not a unique solution, once this relation depends on the number of daily and night flights of the airport. Thus, the use of DNL in airport noise zoning may lead to completely different results for different airports. Thus a new logical airport zoning is proposed based on LAeqD and LAeqN. This airport zoning will provide for urban authorities a set of curves and clear application that can be used to produce a compatible urban zoning.