Level Changes of Traffic Noise in Kerman City, Southeast Iran

Abstract

Background: The purpose of this research was to determine the traffic noise level and changes in the Kerman City, southeast Iran in recent years.
Methods: This cross-sectional study was carried out in 2008 to investigate the existing noise situation in Kerman. Sound levels (L_Max, L_Min, L_eq, L₉₉, L₉₀, L₅₀ and L₁₀) were determined throughout 13 stations using sound level measurement system (model, CEL-440). Number of passing vehicles was also assessed at the sampled stations.
Results: Sound level in all sampled stations was higher than Iran and World Health Organization guidelines. Comparison of L_eq in different hours using statistical tests showed significant difference between different hours with 95 % confidence coefficient (P=0.01). Comparison of L_eq throughout the week also showed that there was a significant difference (P=0.001) between Friday and workday. The comparison of L_eq with the number of passing vehicles using Pearson correlation statistical test showed significant difference between the number of heavy vehicles passed and the level of L_eq (P=0.001). It also showed that number of heavy vehicles caused the most noise levels.
Conclusion: The results of this study compared to a similar study conducted in 1999 showed an increasingly high noise level. Noise level increased from 1999 to 2008 by 3.89 % which is indicative of an increase in noise emission sources.