Determinants of respiratory tract aerosol generation in a diverse clinical population.

<bold>Background:</bold> Respiratory infections are transmitted in part by aerosol. We previously reported aerosol generation in healthy volunteers and found it is individuals coughing and performing forced respiratory manoeuvres that generate aerosol, not medical procedures. <bold>Objectives:</bold> To measure respiratory aerosol generation in a diverse population, exploring the impact of demographic, physiological and clinical factors. <bold>Methods:</bold> Healthy volunteers, people with stable chronic lung disease, and acute respiratory tract infections were recruited. Aerosols were measured via a non-invasive ventilation mask during manoeuvres such as coughing. Aerosol emissions were sampled using Optical and Aerodynamic Particle Sizer systems. <bold>Results:</bold> 130 people were recruited across two hospitals. There were no consistent differences in aerosol production between healthy volunteers, patients with lung disease and patients with respiratory infection (Figure 1). <fig><object-id>erj;64/suppl_68/OA5457/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig> Regression analysis provide weak evidence for 'productive cough' and 'higher body mass index' increasing aerosol production when coughing, with minimal overall variance explained by the model (R² = 0.117) <bold>Conclusions:</bold> Aerosol generation from the respiratory tract is not affected by lung disease or acute infection. Clinical and demographic factors did not fully explain variability in aerosol generation. This has implications for infection control policies in the clinical setting.