Audible and infrasonic noise levels in the cabins of modern agricultural tractors — Does the risk of adverse, exposure-dependent effects still exist?

Abstract

Introduction:The agricultural tractor is one of the most commonly used vehicles on farms and one of the most prominent sources of noise. This article presents an exemplary assessment of the audible and infrasonic noise levels in the cabins of selected modern wheeled agricultural tractors. Materials and Methods: Operator-perceived audible and infrasonic noise levels in the cabins were examined for 20 types of modern tractors during typical conditions of work. The tractors had been in use for no longer than 3 years, with rated power between 96 kW and 227 kW, designed and produced by world-renowned companies. Noise level measurements were performed in accordance with PN-EN ISO 9612:2011 (ISO 9612:2009. Results: Audible noise levels (A-weighted) ranged from 62.1 to 87.4 dB-A (average: 68.2 to 83.8 dB-A) for different work tasks. The factors influencing noise levels include performed tasks, soil, weather conditions and the skills of individual drivers. In spectrum analysis, the highest noise levels occurred at frequencies 250 Hz, 1 and 2 kHz. Infrasound noise levels (G-weighted) ranged from 87.3 to 111.3 dB-G. The driver-experienced exposure to infrasound was found to increase significantly when the vehicle was in motion. Conclusions: Average audible noise levels have no potential to adversely affect the hearing organ during tasks performed inside the closed cabins of the analysed modern agricultural tractors. Due to the relatively low audible noise levels inside the cabins of modern agricultural tractors, non-auditory effects are the only adverse symptoms that can develop. Modern agricultural tractors emit considerable infrasonic noise levels. All tractors introduced into the market should be subjected to tests with regard to infrasonic noise levels.

The influence of tractor exploitation time on the generated noise level

“…It was obvious that noise levels are lower for a tractor equipped with a cab, which facilitates better working conditions. The results of measured noise levels ranging from 62,1 dB to 87,4 dB taking place when different tasks were performed by a tractor with powers ranging from 96 kW to 227 kW, [2]. The same author established that an average measured noise level does not negatively affect tractor operators.…”

“…6 shows a lower standard error of 0,6001 for older tractors (2). The standard error of 1,0319 for younger tractors is significantly higher.…”

“…1 reveals that at 1100 min −1 the standard error of 0,3306 is lower in the case of younger tractors (1). On the contrary, the standard error of 0,3598 is higher for the older tractors (2). A lower standard error of 0,2998 for older tractors (2) and higher standard error of 0,4023 was determined for younger tractors (1) at 1800 min −1…”

A Hearing Loss Prevention Outreach Program for Farmers and Motorsports Enthusiasts

“…[12][13][14][15] Newer, modern tractors with enclosed cabins for the driver can lower daily noise exposure to safe levels. 16 However, many farmers do not remain inside tractor cabs the entire work day. Other noisy equipment is also frequently utilized on farms, such as grain dryers and chainsaws, which can reach levels of 110 dBA.…”

Exposure to infrasonic noise in agriculture

“…Although exposure to audible noise has been examined in many publications thet sources of infrasound in agriculture have not been fully examined and presented [1,2]. Infrasound consists of acoustic oscillations the frequency of which is below the low frequency limit of audible sound (16 Hz, more commonly considered as 20 Hz) (IEC, 1994), but this definition is incorrect as sound remains audible at frequencies well below 16 Hz [3].…”