A novel approach of aerosol emissions under different expiratory activities- an experimental study

Abstract

The behavior of breathing aerosols has become an enigma after the large number of diseases that are transmitted by air. The current project presents an experimental analysis providing results on the characteristics of aerosols when exhaled into the environment after different respiratory actions. The study involved 24 participants (12 women and 12 men) aged between 20 and 30 years. The respiratory actions of the individuals were analyzed using the Aerodynamic Particle Sizer (APS). The designed configuration is based on the collection of aerosols by means of a funnel; designed, optimized and studied in this research. The respiratory actions chosen for the study were breathing, talking and coughing. As a novelty, the analysis of what is produced by the combination of talking and coughing in the same period is included, thus providing new data on real situations experienced by individuals in their daily lives. The results show that cough generates aerosols with an average particle concentration of 9.039 cm⁻³ being the highest mean value analyzed, followed by respiration with a value of 1.493 cm⁻³. The mean mass concentration generated in the expiratory activity of respiration generates an average of 1.295 µg m⁻³, while the action of coughing multiplies that value by ten obtaining a total mass of 11.81 µg m⁻³. The combination of two respiratory actions, such as coughing and talking in the same period compared to just talking, shows very similar values, both in particle number concentration and mass. The size distributions almost overlap, making it evident that there is not much difference and the coughing action hardly influences the 90 s period analyzed when talking occupies more space.