Investigation of noise pollution in Ground Safety section of Mehrabad Airport and its relation with employees hearing loss

According to previous researches, working at the airport is one of the most vociferous jobs in the world. Airport workers are at risk of noise induced hearing loss. The present study was done to evaluate the Sound Pressure Level (SPL) in the closest aprons to Ground Safety department at Mehrabad airport and to investigate the effect of airport noise on the employees of this department. Evaluation of SPL in the given aprons was done using sound meter and sound analyzer. Measurement stations at specific intervals to the sound source were identified inside and outside of the participants 'workplace and SPL was measured at night and day. The mean estimated values were compared with those presented by Ministry of Health. The annual participant's audiometry information was extracted from medical records. Then a self-administered questionnaire was distributed among the study sample in order to measure quality of noise exposure. The questionnaire was developed based on three general criteria including the knowledge toward the noise pollution, job satisfaction, and the exposure to the noise source; and the purpose of this questionnaire was to find the relationship (correlation) between these parameters among the study population. The measured equivalent for 8 hours noise exposure was obtained 94 dB(A) and no relation was observed between octave band sound of aircraft and recorded audiometry. Analysis of the questionnaire showed that people with more knowledge about noise pollution used more hearing protective equipment. Subsequently, by using more hearing protection equipment the level of hearing loss was reduced significantly (P<0.05). There was a significant and negative correlation between noise exposure and job satisfaction, as well (P<0.05). Also there was a significant and negative correlation between using of ear muffs and catching Noise-Induced Hearing Loss (P<0.1). The percentage of noise-induced hearing loss was calculated 51.4% among study sample. The noise exposure of employees of Ground Safety working in Mehrabad airport was higher than the permissible limit which implies the necessity for use of earmuffs and implementation of noise reduction programs.