Analysis of the impact of low-frequency traffic noise in two South American cities

Abstract

Traffic noise is one of the most important sources of annoyance in South American cities. The obsolescence of vehicles and the lack of controls are two of the main causes of this noisy traffic. Since the legislation considers it as a typical source of urban noise, the metric to analyze traffic noise is the A-weighted dB (so-called dBA); therefore, it is not easy to analyze its real impact on human health because low-frequency sound levels are strongly reduced by A-weighting. This article presents the results of a field study carried out in Lima (Peru) and Montevideo (Uruguay) to analyze the impact of traffic noise focused the lowest frequencies, in the range defined by ISO (1/3 octave bands between 16 and 200 Hz), and the WHO recommendation using the whole audible frequencies. The data for Lima were taken in places where a specific acoustic EIS has been required, while the Montevideo´s one were for its noise map. The spectra were processed looking for a representative low-frequency traffic noise metric, so the values of (C–A) obtained byWHO recommendation and ISO recommendation are compared. The expected impact on human health is much more worrisome when low-frequencyrange are explicitly considered.