Chulalongkorn Medical Journal


Background: During the Coronavirus disease (COVID-19) pandemic, emergency medical service (EMS) workers areexposed to infectious particles in closed spaces such as in the ambulance. Few studies have demonstrated the effectiveness of ambulance ventilation system in reducing airborne particles.

Objective: To assess the effectiveness of an ambulance ventilation system in reducing the volume density of airborne particles and return-to-background time.

Methods: Aerosol particles of various sizes were administered into the cabin via nebulization for one minute. The aerosol volume concentrations of particles at 0.5-1; 1-2.5; and 2.5-5 microns were measured with three different ventilation rates (switched off, medium and maximum) at 3 different seat positions (front, side, rear).

Results:The return-to-background time was significantly different (p

Conclusion: There is increased clearance of airborne particles at higher ventilation rates. Installation of this system in the ambulance cabin may provide better control of aerosolized particle suspension which will minimize risk of airborne transmission among the ambulance workers.



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