Effects of Tonal Noise on Workers' Annoyance and Performance

Numerous references indicate that the subjectively assessed tonal noise annoyance is higher than that of broadband noise. There are no criteria for the impact of tonal noise in assessing the occupational environment for both indoor areas and workplaces.

The study participants included 50 people who met the audiometric qualification criteria. The research method employed both a questionnaire survey and computer psychological tests checking work performance, attention level, and memory. Four types of generated test signals were developed (filtered noise - A and three signals with tonal components 125, 1600, and 8000 Hz - B, C, and D) at the same sound level A of 55 dB. Test signals C and D were assessed as causing the greatest annoyance and as the loudest.

The results of some tests and the assessment of annoyance and of the volume of test signals containing medium and high frequency tonal components were correlated with the participants' noise sensitivity, determined on the basis of a questionnaire. Although there are no statistically significant differences, it was observed in most cases for signals with C (1600 Hz) and D (8000 Hz) tonal components that the results (mean values or median values) of psychological tests deteriorated with respect to a noise signal without tonal components (A) - a smaller number of calculations, a smaller number of correct responses, more errors made.

These results, combined with those of the questionnaire survey, justify the introduction of the tonality annoyance criterion for workstations where, among other things, focusing one's attention is required.