Determinants of noise annoyance in teachers from schools with different classroom reverberation times Jesper Kristiansen a, * , Søren Peter Lund a , Per Møberg Nielsen b , Roger Persson a , Hitomi Shibuya a a The National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100 Copenhagen, Denmark b Akustik Aps, Trekronergade 19, DK-2500 Valby, Denmark article info Article history: Available online 23 August 2011 Keywords: Classroom noise Classroom acoustics Occupational noise Indoor environment abstract A high proportion of school teachers report that they are disturbed by noise during teaching. The aim of the study was therefore to identify determinants of self-reported noise exposure and disturbance attributed to noise among secondary school teachers (n ¼ 419) in 10 schools in Copenhagen, Denmark. The schools were selected to show contrasts in classroom reverberation times (RT), and were classified as “Short RT” (3 schools, mean RT 0.41e0.45 s), “Medium RT” (3 schools, mean RT 0.51e0.55 s) and “Long RT” (4 schools, mean RT 0.62e0.73 s). Significant determinants of self-reported noise exposure were a high number of children in the class, young age of the children, and low teacher seniority. “Long RT” classification was of borderline significance. Significant determinants of disturbance attributed to noise from children in the class were teacher seniority and “Long RT” acoustic classification of the school. The associations between work characteristics and noise disturbance measures were attenuated by low self- rated work capacity, suggesting that the consequences of noise and poor acoustics may not be limited to disturbance attributed to noise, but may have a wide negative impact on the perceived working environment. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction School teaching is a knowledge transfer activity that entails speech communication and a relatively high cognitive workload, both of which are critically dependent on high signal-to-noise levels and good acoustical conditions (Hughes & Jones, 2003; Kjellberg, 2004). From this perspective it is alarming that the prevalence of noise problems is high among school teachers. For example, in the Danish Work Environment Cohort Study (DWECS) 2005 survey, 71% of the teachers reported that they were exposed to loud noise for at least ¼ of the working hours, which is consid- erably higher than the proportion of 32% among Danish employees on average. That voice problems are also more prevalent in teachers than in many other occupations (Smith, Lemke, Taylor, Kirchner, & Hoffman, 1998) further underscore that the acoustical working environment in classrooms can be quite demanding (Pekkarinen & Viljanen, 1991). Despite this knowledge it is clear that the potential consequences of noise and poor acoustical working conditions on the physical and mental health of teachers have not been suffi- ciently studied. Annoyance is the most direct reaction to work-related noise (Kjellberg, 1990). Known contributing factors to noise annoyance encompass both physical characteristics of the noise such as the sound level and tonal components, as well as non-sound factors such as gender, hearing status, the task engaged in, predictability of the sound etc. (Kjellberg, 1990; Kjellberg, Landstrom, Tesarz, Soderberg, & Åkerlund, 1996; Landström, Åkerlund, Kjellberg, & Tesarz, 1995). However, it is not known to what extent these determinants also matter to school teachers, or indeed which sound sources causes most annoyance. Among the potential determinants of noise annoyance is poor classroom acoustics. Among the parameters used to characterize classroom acoustics, reverberation time (RT) has received partic- ular attention because of the central role it has in determining the role of reflected speech sounds. Reflected speech sounds that arrive shortly (<50 ms) after the direct sounds serve to amplify the direct speech sounds, while reflected speech sounds that arrive later tend to mask the direct speech sounds. Not only does this make the speech more difficult to comprehend, it also impairs memory consolidation of what is heard, which is a consequence that is highly relevant considering the purpose of teaching (Kjellberg, 2004; Ljung & Kjellberg, 2009; Ljung, Sörqvist, Kjellberg, & Green, 2009). Moreover, when there are multiple talkers in the same room (a situation that often happens in the classroom during group * Corresponding author. Tel.: þ45 3916 5259; fax: þ45 3916 5201. E-mail address: jkr@nrcwe.dk (J. Kristiansen). Contents lists available at SciVerse ScienceDirect Journal of Environmental Psychology journal homepage: www.elsevier.com/locate/jep 0272-4944/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.jenvp.2011.08.005 Journal of Environmental Psychology 31 (2011) 383e392