Evaluation of Noise Reduction Interventions in a School.

INTRODUCTION: Noise in the school environment has been a major concern in many countries around the world. Students need a favorable signal-to-noise ratio in the classroom to ensure adequate speech intelligibility, which is directly dependent on the acoustics of the classroom and favorable noise levels in these environments.

OBJECTIVE: To evaluate the effectiveness of physical, organizational, and educational interventions to achieve noise reduction in a school.

METHODS: Presentations on the effects of noise were made to school administrators, teachers, and students (educational activities), and also to the students' families. Then, thermoacoustic treatment, changes in break times, equipment maintenance, and scheduling of students' departure were applied. Sound pressure levels were measured before and after interventions for the unoccupied and occupied classroom conditions (n = 11 classrooms) and of the school's outside areas (n = 4). Self-administered printed pre- and postintervention multiple-choice questionnaires were completed by the students in the classroom. Measures of the signal-to-noise ratio of the teachers' voice before and after the interventions were also conducted (n = 3 classrooms). The interventions included installation of an acoustic ceiling, installation of air-conditioning, and replacement of the existing furniture with wood furniture.

RESULTS: Comparing the pre- and postintervention questionnaires, the Annoyance Index was reduced from 0.78 to 0.59. The tinnitus reported by the individuals increased significantly in the postintervention questionnaire (p < 0.001). Significant reductions in noise levels in both unoccupied and occupied classrooms were observed. There was also an improvement in the mean signal-to-noise ratio in the evaluated classrooms (n = 3) from +7.5 to +8.4 dB.

CONCLUSION: Subjective measures and objective assessments demonstrated that both physical and educational interventions had a positive effect on short-term changes in habits and noise reduction in the school environment.