Pawlaczyk-Luszczynska M., Dudarewicz A., Sliwinska-Kowalska M.

The aim of the study was to recommend methods for assessing low frequency noise (LFN) in the occupational environment to prevent annoyance and its effects on work performance. Three different measuring methods were proposed: (i) method I - frequency analysis in 1/3-octave bands from 10 to 250 Hz, (ii) method II - determination of equivalent-continuous A-weighted sound pressure level (SPL) in the frequency range 10-250 Hz and introduction of the penalty for tonal character of noise, and (iii) method III - based on equivalent-continuous A-weighted SPL corrected due to the presence of low frequencies and tonal character of LFN. As recommended noise limits for method II and III, 50 and 55 dB were proposed, respectively. On the other hand, various criterion curves were assumed for method I. The proposed criteria were verified in the laboratory and field investigations. The laboratory study included 55 volunteers, aged 21.8 2.1 years, with normal hearing (<25 dB HL). Subjects listened to different noises at SPL of 45 65 dBA, and evaluated annoyance using a 100-score graphical rating scale. In the field study, the subjects, 28 male workers, aged 43.1 5.1 years, exposed to LFN at SPL of 48 61 dBA, were asked to rate noise annoyance at workplace using similar graphical scale. The subjective ratings of LFNs were compared to objective results from various assessing methods. The relations between annoyance and excesses of proposed limits were analyzed using Pearson correlation coefficient (r). The obtained results show that the subjective ratings were correlated with all proposed criteria (0.51?r?0.63 p<0,01). However, in the laboratory exposure conditions the best relation was found in case method I and criterion curve based on hearing threshold level (r=0.61), while during field study - method II (r=0.63).