Annoyance Related to Low Frequency Noise in Subjective Assessment of Workers

Abstract

The aim of this study was to assess annoyance related to low frequency noise (LFN) in employees of the control rooms and office-like areas. Subjects were 276 workers, aged 26–62 years, exposed to noise at A-weighted sound pressure level (SPL) of 41–66 dB. They were asked to assess noise annoyance at their workplace using a 100 point graphical scale. The subjective ratings were compared with various noise metrics and objective evaluations based on proposed LFN exposure criteria for occupational settings. There was a difference in annoyance assessment related to noise with and without (or with less prominent) low frequency content. Low frequency noise was rated as more annoying even though it was at lower dBA levels. Among the noise metrics, the low frequency A-weighted SPL yielded the highest correlation with subjective evaluations of LFN. There was also a quite good agreement between individual annoyance ratings and limit excesses corresponding to preliminary Swedish and Polish exposure criteria.

Evaluation of annoyance from low frequency noise under laboratory conditions

“…[11,29] Our recent observations from field studies comprising 276 workers confirmed that exposure to LFN in the industrial control rooms and in office-like areas at equivalent A-weighted SPLs (48−61 dB), which was well within current occupational exposure limits, could cause increased annoyance, especially in subjects recognized as more sensitive to this type of noise. [5] Our results were also in line with earlier findings that LFN was rated as more annoying than noise without (or with less prominent) low frequency content at similar dBA levels. Moreover, they suggested that the low frequency A-weighted SPL seemed to be a proper predictor for evaluation of the gravity of the annoyance experienced from LFN at workplace since, among the noise metrics, it yielded the highest correlation with subjective evaluations of LFN.…”

“…Similar results were obtained in the field study during which various evaluation methods were compared with subjective assessment of LFN at workplaces in the industrial control rooms. [5] In this study, a linear relationship between the LFN annoyance rating and almost all analyzed noise metrics was noted. But subjective assessments of LFN were significantly less correlated with HTL-based noise measures (especially L LF Tot and L LF HTL ) in older subjects (experiment II) compared with younger persons (experiment I).…”

“…[19,38] It was also observed in our previous field study cited above, concerning occupational exposure to LFN. [5] For example, Persson Wye et al, [19] (in their article cited below in more detail) showed that exposure to LFN was rated as more annoying by subjects recognized as high-sensitive to this type of noise than by low-sensitive ones. Interestingly, their evaluation of sensitivity to LFN was based on statements or questions taking into consideration subjective sensations related to LFN (e.g.…”

“…These findings did not confirm results from the majority of previous laboratory investigations intended to compare annoyance assessments of various sounds with and without dominant contents of low frequencies [1,2] as well as our earlier observation from field study. [5] On the other hand, higher assessments of LFN annoyance relative to noises without dominant content of low frequencies but similar A-weighted SPLs were not so obvious in laboratory studies dealing mainly with possible influence of LFN on performance. [18−21] Persson et al, [19] found out that subjects executing various high-load tasks for 2 hours reported a higher degree of annoyance and impaired working capacity when working under LFN conditions than those exposed to broadband noise with rather flat frequency spectrum, both at a level about of 40 dBA.…”

“…Moreover, they suggested that the low frequency A-weighted SPL seemed to be a proper predictor for evaluation of the gravity of the annoyance experienced from LFN at workplace since, among the noise metrics, it yielded the highest correlation with subjective evaluations of LFN. [5] The aim of the present study was to investigate annoyance from LFN at levels normally prevailing in the industrial control rooms and office-like areas under laboratory conditions. In particular, it has been attempted to: 1.…”