Bioaerosols are airborne particles with biological origin. They are known to be one of the main transmission routes of infectious diseases in indoor environment where people spend most of their time [1]. It is therefore very important to characterize these particles and their impact on indoor air quality. The Biotrak Real-Time Viable Particle Counter TSI 9510-BD is one of a few devices that can count in real time total and biological particles in the atmosphere. The main objective of this work is to test the Biotrak ability to characterize bioaerosols and their origins in real life conditions such as: empty and full universities classrooms and educative laboratories. The Biotrak was tested in a normal classroom with full occupation (two dimensions available: 25 people and amphitheater of 100 people). The experimental procedure began by counting the particles in the empty classroom for one hour. Afterwards, students and teacher were allowed to enter and remain in the classroom for a usual twohours course. The Biotrak allowed to count the generated particles from the moment the people entered until they all left (and one hour after). It should be noted that these measurements were performed before the COVID outbreak, which means that the people were not wearing masks. The results showed that we could easily correlate the emission of bioaerosols with the various activities in the classroom. Indeed, the number of generated bioaerosols was found to increase when the students entered and left the classroom. In the future, we will investigate the impact of using the protective masks on the generation of bioaerosol in the classroom.