Study of a novel neck-side ventilation system for reducing pollutant exposure

Abstract

Wearable ventilation devices can reduce respiratory exposure in polluted environments. This study investigates a neck-side ventilation system using Computational Fluid Dynamics (CFD) simulations and experimental validation. The system delivers clean air through dual neck vents, deflecting along the face under the Coanda effect to form a clean air layer around the nose and mouth, reducing exposure to pollutants. Key factors, including roll angles, inlet pitch angles, and air speeds, were analysed for their impact on pollutant exposure reduction (PER). Results show that at roll angles of 30° or 45°, the Coanda effect deflects and converges the airflow in front of the face, forming a protective air layer. The pitch angle affects the convergence point, with 40° and 45° angles optimising the clean air layer's position around the breathing zone. Airflow velocity has a secondary impact when optimal roll and pitch angles are chosen. However, in suboptimal combinations, higher airflow velocities improve pollutant shielding, except when the roll angle is 0°, where higher speeds worsen pollutant entrainment into the breathing zone. The system achieves a maximum PER of 75.2 % at a roll angle of 30° and a pitch angle of 45° This study confirms the potential of neck-side ventilation for respiratory protection and provides guidance for optimising design parameters to improve performance in polluted environments.