Supermicron particle deposition from turbulent chamber flow onto smooth and rough vertical surfaces

Deposition to indoor surfaces influences human exposures and material damage from airborne particulate matter. Experiments were conducted to study the deposition of monodisperse particles in the diameter range 0.9–9 μm from turbulent flow onto smooth and rough vertical chamber surfaces. Fluorescent particles were injected continuously into a stirred 1.8-m3 aluminum chamber for a period of several hours. Deposition was measured on smooth glass plates and sandpaper with four different roughness scales that had been mounted on two opposing vertical sidewalls. Deposition velocities were determined as the ratio of deposited particle flux density to airborne particle concentrations. Contrary to expectations, particle deposition onto smooth and rough vertical surfaces was observed to increase with diameter for most conditions, especially for the larger particle sizes. Deposition velocity increased only moderately with increasing surface roughness.