The Effects of Broadband, Tonal and Masked Ventilation Noise on Performance, Wakefulness and Annoyance

Abstract

A laboratory study was designed in order to investigate the effects of ventilation noise on performance, fatigue and annoyance. The study was also designed in order to compare the effects of broadband noise 40 dB(A), tonal noise, 40 dB(A), and tonal noise masked by means of low frequency pink noise, 41 dB(A). The study of performance was based on a figure identification test. The annoyance and fatigue were tested by means of rating scales. The analyses of fatigue also included EEG-recordings. The acceptability of the different types of ventilation noise was also analysed through matching tests. The differences in performance between broadband and tonal ventilation noise were significant and did not show any unambiguous tendency. An insignificant tendency of worse performance during broadband exposure and that the tonal ventilation noise should be more tiring could be observed. The tonal exposure was described as less annoying during work. On the other hand, in the matching tests, the subjects tolerated an insignificantly lower level of the tonal ventilation noise compared to the broadband noise. Comparisons between the tonal ventilation noise and the tonal ventilation noise masked by means of a pink noise, showed that the masked ventilation noise was correlated to ambiguous tendencies towards higher performance, lower fatigue but higher annoyance. In the matching tests, the subjects tolerated a lower level of masked ventilation noise compared to the unmasked ventilation noise. Except for the ratings of fatigue, all differences were below the level of significance p 0.05.

The Influence of Low-Frequency Noise Pollution on the Quality of Life and Place in Sustainable Cities: A Case Study from Northern Portugal

“…In the field of occupational medicine, several studies claim that low-frequency noise is an agent that interferes with the performance of work tasks [25,[27][28][29] and that low-frequency noise can affect mental and physical health.…”

Implications of human performance and perception under tonal noise conditions on indoor noise criteria

“…Landström et al found no significant difference in performance on a figure identification test when comparing a broadband ventilation noise to a second broadband ventilation noise with a tone added at 100 Hz ͑both at L Aeq = 40 dBA͒. 30 However, when comparing the tonal noise to the same noise with a masking pink noise ͑41 dBA͒ added in the frequency range of 50-200 Hz, they found a tendency toward better performance, higher wakefulness, higher annoyance, and lower tolerated levels under the pink noise added exposure. 30 The fact that differences were seen when comparing the tonal noise to the masked noise but not when comparing the tonal noise to the broadband noise indicates that the types of noise conditions used play a strong role.…”

“…Much work has been conducted on loudness and annoyance of tones in noise, [27][28][29][30][31][32] but little has been done to correlate these with commonly used indoor noise criteria systems. Modern HVAC systems are replete with examples of pure tones.…”

“…The effect of excessive low frequency background noise on task performance has been the topic of several projects. 30,[36][37][38][39][40][41][42][43] Some of the conclusions from these studies are that task performance can be affected by background noise and the frequency character of the noise is an important consideration. These studies provide important information about the relationship between noise and performance but generally do not relate the results to indoor noise criteria.…”

Determining annoyance thresholds of tones in noise

“…Results indicate that the presence of tones can impact perception or performance (Landström et al 1991(Landström et al , 1994Holmberg et al 1993;Ryherd and Wang 2010), but none of the investigations could provide guidelines for what the threshold of annoyance for tones in noise should be across a wide range of tonal frequencies. Further work is required to link the degree of tonalness in noise to human annoyance thresholds.…”