Objectives. Annoyance from transportation noise is well characterised but little is known about occupational noise. We investigated the relation between occupational noise exposure level, the use of hearing protection devices (HPD), and noise annoyance.
Methods We studied 452 industrial workers and 68 financial workers who post shift reported noise annoyance during work on a 5-point scale. Noise exposure level was recorded every 5 seconds at the dominant shoulder for 24 hours and we calculated the LAeq value for work hours. For 342 workers who kept a HPD diary, we subtracted 10 dB from every noise recording obtained during HPD use and estimated the LAEq value at the ear.
Results The mean measured noise exposure level was 80.0 dB(A) [range: 55.0–98.9] and the mean estimated level at the ear 77.8 dB(A) [range: 55.0–94.2]. Fifty-one percent of workers exposed at a measured noise level ≥ 85 dB(A) were annoyed (the upper 3 points on the annoyance scale) and 14% highly annoyed (the upper 2 points). In a logistic regression model that also adjusted for neuroticism, annoyance increased monotonously with 6% per dB(A) (OR = 1.06, 95% CI 1.02–1.09). A slightly lower trend was seen per estimated LAEq level at the ear (OR = 1.04, 95% CI 0.99–1.07). HPD use was strongly associated with annoyance when adjusted for noise exposure level (OR 2.3, 95% CI 1.3–3.9).
Conclusions Increasing occupational noise exposure level was associated with increasing prevalence of annoyance but at a much lower annoyance level than seen for transportation noise. We documented no gainful effect of hearing protection, but the opposite. An obvious explanation is that noise annoyance is not solely a question of the amount of noise appearing at the ear but also other characteristics of a noisy work environment; furthermore, that HPD use is predicted by noise sensitivity and other individual characteristics that are associated with noise annoyance.