A study carried out by the Spanish Organization of Consumers and Users, OCU, performed measurements of the noise levels in 10 elementary schools in Madrid and Barcelona, Spain. The results showed noise levels outside the buildings varying between 53 and 76 dB during classes.
Inside the classrooms, seven out of ten schools exceeded the standard permissible noise level of 40 dB established by Spanish regulations. Considering the limit recommended by the World Health Organization, WHO, 35 dB at school, nine out of ten schools fail to meet the recommended levels.
A Chilean study found even worse conditions in Chile.
Pedro Matamal, Head of the Otolaryngology Department, and engineers from Santiago University investigated noise levels in nine schools in Santiago de Chile.
Noise levels inside the classrooms were above 50 dB, reaching 60 dB occasionally. Forty percent of the students said they had difficulty understanding what the teacher said due to the noise. In 50percent of the schools the average noise level measured was 70 dB.
WHO recommends maximum noise levels of 35 dB in schools. As a rule of thumb, maximum noise levels of 45 dB is recommended outside buildings at night and 55 dB during the daytime. Noise levels between 60 and 65 dB are considered uncomfortable.