Acoustic comfort: an overview of human exposure to environmental noise in a public transport vehicle in the capital of Mato Grosso

Abstract

The concern with human exposure to environmental  noise from interiors is a constant target of studies, due to the increase of noise-generating sources in urban areas and the risk of possible psychophysiological effects to its occupants. In this scenario, the vehicle environment for urban passenger transport has aroused great interest mainly for the constant flow of passengers and because they are subject to events intrinsic to the urban environment, such as traffic noise. Thus, this study evaluated human exposure to environmental noise inside public transport vehicles in Cuiabá, Mato Grosso, with the objective of investigating health iness and acoustic comfort. Variations in noise levels (dB(A)) were monitored in three predefined points in the vehicle interior, in the morning, evening and evening hours on three consecutive working days in August 2018 and February 2019. For acoustic comfort analysis, we used the calculation of the continuous equivalent noise level (L_eq) and the statistical noise indexes L₁₀ and L₉₀, according to CETESB/L11.033 (1992) Technical Standard, and the results compared to the tolerance limits established by the Ministry of Labor and Employment (NR-15 and NR-17) and the World Health Organization (WHO). In all samples, estimated values of L₁₀ and L₉₀ above 90 dB(A) were observed, differing from the limits recommended by the WHO and NR-17, characterizing the environment as very noisy and acoustically uncomfortable. This is done, it is possible to conclude that the environment is potentially harmful to the health of the occupants of the vehicle, in particular the driver's seat.