title: The effects of acoustical refurbishment of classrooms on teachers' perceived noise exposure and noise-related health symptoms.
abstract: OBJECTIVE
  To investigate whether acoustical refurbishment of classrooms for elementary and lower secondary grade pupils affected teachers' perceived noise exposure during teaching and noise-related health symptoms.
  
  
  METHODS
  Two schools (A and B) with a total of 102 teachers were subjected to an acoustical intervention. Accordingly, 36 classrooms (20 and 16 in school A and school B, respectively) were acoustically refurbished and 31 classrooms (16 and 15 in school A and school B, respectively) were not changed. Thirteen classrooms in school A were interim "sham" refurbished. Control measurements of RT and activity sound levels were measured before and after refurbishment. Data on perceived noise exposure, disturbance attributed to different noise sources, voice symptoms, and fatigue after work were collected over a year in a total of six consecutive questionnaires.
  
  
  RESULTS
  Refurbished classrooms were associated with lower perceived noise exposure and lower ratings of disturbance attributed to noise from equipment in the class compared with unrefurbished classrooms. No associations between the classroom refurbishment and health symptoms were observed. Before acoustical refurbishment, the mean classroom reverberation time was 0.68 (school A) and 0.57 (school B) and 0.55 s in sham refurbished classrooms. After refurbishment, the RT was approximately 0.4 s in both schools. Activity sound level measurements confirmed that the intervention had reduced the equivalent sound levels during lessons with circa 2 dB(A) in both schools.
  
  
  CONCLUSIONS
  The acoustical refurbishment was associated with a reduction in classroom reverberation time and activity sound levels in both schools. The acoustical refurbishment was associated with a reduction in the teachers' perceived noise exposure, and reports of disturbance from equipment in the classroom decreased. There was no significant effect of the refurbishment on the teachers' voice symptoms or fatigue after work.
authors.affiliation: The National Research Centre for the Working Environment, Lersø Parkalle 105, 2100, Copenhagen, Denmark. jkr@nrcwe.dk.
authors.forename: Jesper
authors.initials: J
authors.lastname: Kristiansen
authors.affiliation: The National Research Centre for the Working Environment, Lersø Parkalle 105, 2100, Copenhagen, Denmark.
authors.forename: Søren Peter
authors.initials: SP
authors.lastname: Lund
authors.affiliation: Department of Psychology, Lund University, Lund, Sweden.
authors.forename: Roger
authors.initials: R
authors.lastname: Persson
authors.affiliation: Danish Centre of Educational Environment (DCUM), Randers, Denmark.
authors.forename: Rasmus
authors.initials: R
authors.lastname: Challi
authors.affiliation: Danish Centre of Educational Environment (DCUM), Randers, Denmark.
authors.forename: Janni Moon
authors.initials: JM
authors.lastname: Lindskov
authors.affiliation: Akustik Aps, 2500, Valby, Denmark.
authors.forename: Per Møberg
authors.initials: PM
authors.lastname: Nielsen
authors.affiliation: AB Akustik, Skanderborg, Denmark.
authors.forename: Per Knudgaard
authors.initials: PK
authors.lastname: Larsen
authors.affiliation: Department of Civil Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark.
authors.forename: Jørn
authors.initials: J
authors.lastname: Toftum
mesh_terms: D000162:Acoustics; D000328:Adult; D006970:Disorders of Excessive Somnolence / Q000209:etiology; D005160:Facility Design and Construction; D005221:Fatigue / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009623:Noise, Occupational / Q000009:adverse effects / Q000517:prevention & control*; D016273:Occupational Exposure / Q000009:adverse effects / Q000517:prevention & control*; D010465:Perception; D012574:Schools; D013018:Sound Spectrography; D011795:Surveys and Questionnaires; D013663:Teaching; D014832:Voice Disorders / Q000209:etiology
keywords: Acoustical working environment; Classroom acoustics; Extra-auditory effects of noise exposure; Intervention; Noise exposure; Well-being