With the rapid development of information technology equipment and its use in the teaching and learning activities, the working environment (especially indoor air quality) in which students and pupils spend a great deal of time in educational institutions has been changing. Therefore, special attention must be paid to indoor air quality and comfort. It is of great importance to maintain indoor air quality in an object, such as information technology classrooms, where a large number of students spend long periods of time. Poor indoor environment can negatively affect scholarly performances and cause discomfort and poor work performance. The problem of indoor air quality in educational institutions can be more serious than in other types of objects, because of the higher concentration of students and information technology equipment. This paper analyzes the changes in air quality in an information technology classrooms, when occupied with students, for the period from March to April. The changes of indoor air temperature, relative humidity, and carbon dioxide concentration are monitored in the classroom, as well as outdoor temperature and relative humidity. Several cases are studied: the classroom with closed windows and doors (closed classroom), the classroom with natural ventilation, the classroom cooled with a split system (cooled classroom). Responses of students are followed for each case. The analysis is performed based on the measurement results and numerical simulations using the computational fluid dynamics package, and measures are proposed to improve the indoor air quality in the considered classroom.