Comparison of equivalent noise pollution and traffic noise index in different cities of Qazvin province (2010)

  Background: Noise pollution in cities is one of the most important health problems which is growing in severity.   Objective: To determine the level of equivalent noise and traffic sound in various cities of Qazvin province.   Methods: This cross-sectional study was conducted in the winter of 2010 in Qazvin . Measurements were performed by the sound level meter 1353H (TES, Taiwan). The main streets and intersections on the city maps were considered as measuring stations. The levels of equivalent noise, statistical noise, and traffic noise were measured based on the ISO 1999 method approved by the Environmental Protection Organization . Data were analyzed by one side, two side, paired t-test.   Findings: Of total measuring stations, 63% were found to have equivalent noise level higher than the standard recommended for residential-commercial areas and 24% within the standard levels.   Conclusion: In all cities under study, the equivalent noise level was higher than that recommended for residential-commercial areas. The daily equivalent of noise index did not change at different times, indicating a uniform sound level from traffic and acoustic fields.