Investigation of noise annoyance and audiometric results of Tehran subway workers and their relation to noise exposure

Introduction: One of the most important sources of pollution is the noise generated by traffic and transportation, especially the urban railway system (metro), thus this study aimed to assess the noise exposure of Tehran Metro employees and its relation with noise annoyance and audiometric results of employees. Materials and methods: Measurement was done by using a TES-1351B sound level meter recommendations for all employees which consists of the staff of the station affairs and the staff of the administrative department. A self-reporting questionnaire on workplace noise annoyance were distributed to the employees and then audiometric were used to measure the employees hearing level. Results: The average noise exposure in platform workers was 79.3±10 dB and in control room workers was 56.5±6.9 dB. A significant difference was found between the average noise exposure in the employees of the two groups (control room-platform) (p-value=0.001). Based on the results, noise in the work environment was significantly more annoying for people working in metro line 1 than in line 6 (p-value=0.025). Conclusion: These results show that in general, due to the sound pressure level of 10% of the platform employees being higher than the permissible limit and the increase in the level of noise annoyance of the employees at the frequency of 8 kHz, it is necessary to plan and adopt administrative and technical-engineering measures to reduce the level of noise pollution to about it seems necessary to allow the standard.