Determination of noise pollution propagated from agricultural tractors and its driver's noise exposure level

Application of agricultural machineries such as tractor has been yielded a considerable development in different agricultural activities and productions. However, noticeable health problems such as noise pollution impact the users of these off-road vehicles. The purpose of this study was to determine the noise level induced by agricultural tractors and to evaluate the driver’s noise exposure level. The sound pressure levels of three brands of tractor include John Deere, Ferguson and Romani were measured by sound level meter model Tes-1358. The characteristics of place for measuring tractors noise pollution were determined based on the ISO standard No 7216, 5131. The acquired data was analyzed using spss16 software. The results showed that the highest and the lowest noise level around the tractors were 83.8 dB (A) and 73.9 dB (A) for the John Deere and Romani, respectively. The effect of different transmission gears on the noise level of tractors was not statistically significant Pvalue>0.05. While, the effect of the tractor engine speeds on the noise level was statistically significant Pvalue<0.01. The exposure time of the most of drivers was frequently about 8 hour or more In this regards, the exposure levels of the tractor’s drivers to noise measured between 85-90 dB (A) were higher than the Iranian occupational exposure limit (85 dB (A)).Moreover, mean noise reduction rate of exsisting room which was used upon the typical tractor’s body was 9.5 dB in one octave band. Application of standard cockpit and expansion mufflers can effectively reduce noise pollution emission and driver’s occupational exposure. Moreover, regular preventive maintenance and effective hearing conservation program including annual audiometry, hearing protection device, occupational health training for drivers must be implemented.