Air traffic noise maps have been drawn for Istanbul Ataturk International Airport. With the establishment of these maps, a study was conducted by using subjective and objective methods in order to assess the noise annoyance levels of students and teachers of schools around airport. Questionnaires and intelligibility tests were designed (with different questions for teachers and students) in order to measure the effect of noise among students and teachers as the classrooms' users. A total of seven hundred and twenty (720) students and one hundred and fourteen (114) teachers completed the questionnaire, which was mainly designed to define their ability to differentiate different noise sources (originating both internally or externally), and their annoyance levels with these noise sources. The results reveal that overall, students tend to be more annoyed than teachers; aircraft noise is considered the main external noise source and students' chatter is rated the main internal noise source for both groups. Parallel to the annoyance study, internal and external noise measurements have been carried out to provide information on typical noise levels, to which children are exposed at school. In order to evaluate the acoustical quality of classrooms, four elementary schools within a 5 km radius of the airport were selected and three acoustical parameters have been investigated: background noise level, reverberation time and sound insulation. Finally, in one of the selected school's classrooms, a two-stage improvement study was realised. Results revealed the striking effect of lower reverberation values on increasing speech intelligibility.