Aim: The aim of the study was to determine the quantitative value of high-risk aerosol generation during surgery. Background: Coughing is commonly used as a reference of high-risk aerosol generation during surgeries and other clinical procedures. Those procedures during which aerosol generation exceeds the amount of aerosol produced by coughing are referred to as high-risk AGPs. However, no golden standard about quantitative levels of high-risk aerosol generation exists. Methods: 37 healthy volunteers recruited to cough in the operating room. Aerosol particles, with the size of 0.3-10 µm, generated during coughing were measured with Optical Particle Sizer from 40cm, 70cm and 100cm distances. The distances reflected to potential distance where the staff is working during surgeries. Volitional coughs were compared to involuntary coughs measured with same set up during extubations. Results: A total of 306 coughs were measured. Total aerosol concentration during coughing averaged 1.706 ± 10.802 (range 0.000 – 88.157). Highest aerosol concentrations were measured furthest from the source. No difference between volitional and involuntary coughs were observed. Discussion: The aerosol concentrations, measured in this study can be used as a reference level for high-risk aerosol generation in the operating room environment when assessing the risk of operating room staff´s exposure for aerosol particles