level changes of traffic noise in kerman city, southeast iran

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 , l 99 , l 90 , l 50 and l 10 ) 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.