This study presents some field measurements in an operating room of air velocity, ambient temperature and particle counts on the operating table. Moreover, computational fluid Dynamics analyses of the operating room were performed and compared with the measurements. Measurements were taken under the preferred operating conditions by surgical staff (at 19 degrees C) and then at different ambient temperatures (from 20 to 22 degrees C, varying by one-degree increments) and average inlet air velocities (V-j) (0.1 and 0.2 m/s). The preferred one by surgical staff is 0.1 m/s and the maximum that can be reached is 0.2 m/s, with the current system. The results show that the particle count decreased at V-j of 0.2 m/s and low temperatures.