Assessment of Airborne Cross-infection Risk Across Various Body Orientations in Indoor Airflow Environments

This study aims to evaluate airborne cross-infection risk under different discharge angle (-20°, 0°, and +20°) and supply temperatures (18, 25, and 30 °C) of an air-conditioner, with various body orientations (face-to-face, side-by-side, and back-to-back). Field experiments on particle dispersion were conducted within a full-scale test chamber using a manikin-shaped particle generator and detector with simulated particles (NaCl). Initial trends in particle transmission varied with body orientations. Meanwhile, the cross-infection risk was lower at -20° and higher at +20° under a supply temperature of 25°C for all body orientations. However, discharge angles associated with lower or higher cross-infection risk varied with changes in supply temperatures. The findings indicated that body orientation is a crucial factor influencing cross-infection risk, and careful adjustment of discharge angles and supply temperatures is essential to prevent airborne cross-infection in such airflow environments.