Traversing along the lines of intuition and now being recently confirmed by a promising Mathematical Model worthy of providing promising results, it should come as no surprise that Respiratory Droplets from a Cough or Sneeze travel farther and last longer in Humid and Cold Climates than in Hot and Dry ones, as per the study on Droplet Physics headed by Er. Abhishek Saha and his team at the University of California.
Based on the Fundamental Approach of Collision Rate Theory based on First Principles so that there are no Fitting and Compromises involved (unlike other models around), such a Model comes as a boon, aiding us in our understanding of the Role of Droplets in the spread of Respiratory Viruses; COVID-19 would be a perfect candidate. Their work connects population-scale human interaction with Micro-Scale Droplet Physics Results on how far and fast droplets spread, and how long they last.
At the very Fundamental Level of a Chemical Reaction there lies the Collision of Two Molecules and the Frequency of their Collision gives us a measure of how fast the reaction is progressing. "It's exactly the same here; how frequently healthy people are coming in contact with an infected droplet cloud can be a measure of how fast the disease can spread," says Abhishek Saha.
The Team reported that with varying weather conditions, respiratory droplets travel between 8 feet and 13 feet away from their source before evaporating, without even accounting for wind, they also found that droplets in the range of 14-48 microns possess higher risk as they take longer to evaporate and travel greater distances. Smaller droplets, on the other hand, evaporate within a fraction of a second, while droplets larger than 100 microns quickly settle to the ground due to weight.
All of the above results further the cause of Wearing Masks and ensuring the usage of effective respiratory equipment, not only for our safety but also for all those around us.
Currently, the model suffers from idealized parameters and other limitations but the team is already working to improve the model’s versatility, the next investigations already underway are concerned around Respiratory Droplets which settle on commonly touched surfaces.