Experimental of the Distribution and Direction of Droplet Movement Using a High-Speed Camera

Droplets are liquids or splashes of water that are expelled through the respiratory tract when a person talks, coughs, or sneezes. The average size of the droplets released during sneezing is > 5 µm with a distance of < 1 m. Meanwhile, when speaking, it is 5 µm at a distance of 1 m, which is often called nuclei or respiratory droplets. Due to their smaller sizes and the inability to observe with the naked eye, the direct spread of infections through these droplets is a major factor in the increase in disease cases. Therefore, this research is focused on the set-up of droplet observation instrumentation in the room, where the velocity of airflow is neglected. The novelty lies in determining the size distribution of droplets produced and examining the transmission speed when someone sneezes. The results showed that the set-up successfully identifies the droplets expelled during sneezing. The mucosal sac expands and is dispersed and retracted, which makes the ligaments to be visible when pulled or detached from the mother's pouch, causing the sac to disintegrate and form droplets. Based on observations, the number of droplets produced when sneezing is approximately 109 particles, where 39% are 5 µm and 61% are above 5 µm, with a speed of 2.08 m/s.