The influence of glottal and respiratory factors on aerosol emission during phonation

<b>Methods:</b> Five healthy female adults (22–43 years) sustained vowels across six phonation types: modal register, glottal fry, falsetto register, force whisper, loud modal register, and vowels preceded by /h/ (i.e., h-onset). Aerosol concentration and size distribution (0.1–20 µm) were measured using an aerodynamic particle sizer (APS). Laryngoscopy, conducted in a separate session on sustained /i/, was used to estimate normalized glottal gap (NGG). Exhaled CO₂ range was recorded concurrently with APS as a control for ventilatory variation across tasks. Bayesian regression models assessed relationships between phonation type, aerosol generation, and physiological predictors.