Background: The use of laminar airflow (LAF) to prevent periprosthetic infections has recently been challenged and remains controversial. The aim of this study was to compare LAF performance against turbulent mixed airflow (TMA) regarding particle and microbial elimination. Methods: Particle and microbial load of operating room (OR) air were measured during 48 operations. Microbial sedimentation was collected at four locations (20cm from surgical field and assistant’s table, and 1.3 meters from surgical field and outside protection zone) between incision and suture. The particle content of the OR was measured 20cm from the operating field and assistant’s table and 50cm outside the accepted LAF range. The number of people in the OR, duration of surgery and number of surgeons were recorded. Results: The particle load was significantly lower at all three measuring points in the OR for LAF compared with TMA (p <0.001). At 20cm from the surgical field and on the surgeon’s assistant table, there was no microbial sedimentation for LAF in contrast with TMA. The number of persons in the OR correlated positively with microbial load (p = 0.004) for TMA and also particle load (p <0.001) collected 20cm from the operating field. This was not seen for LAF. Conclusion: The results suggest that LAF maintains the surgical field free from bacterial load and airborne particles under real operating conditions.