Detailed predictions of particle aspiration affected by respiratory inhalation and airflow

The effects of air pollution found in the atmosphere and exposure to airborne particles are an important problem in the interest of public health. Exposure to contaminated air under different flow conditions is studied using the latest computational fluid dynamics models. For the first time the upper respiratory airway is integrated into a human body and placed inside a room, facing different airflow speeds (0.05–0.35 m s−1). It was found that the airflow streamlines diverged as it approached the human body, at the torso and accelerated upwards past the face and head before separating at the rear of the head, forming recirculating regions in the wake behind the body. Inhaled particles were tracked backwards to determine its origins. At a plane upstream from the face the locations of particles inhaled form a region known as the critical area, which is presented. This study establishes a better understanding of particle inhalability and provides a step towards a more holistic approach in determining inhalation toxicology effects of exposure to atmospheric particles. ► Integrated model of human respiratory airway, humanoid, and indoor room is modelled. ► Flow near the face shows accelerated flow into the nostril during inhalation. ► Recirculating flow in the wake created behind body can induce pollutants. ► Particle tracking reveals origin of particles and its fate in respiratory airway.