Redundancy of Humidification at Upper Respiratory Tract, a Plausible Cause of Corona Pandemic - A Hypothesis Based on Thermodynamic Analysis-

The respiratory tract humidification transforms inspired air from whatever temperature and humidity it is, to alveolar air at 37°C at 100 % RH (relative humidity). This is a key thermodynamic and heat and mass transfer process and is as critical as the actual respiration. The normal body temperature of humans is also around 37°C. A simple mathematical analysis is done by replacing figures of moisture content for 100% saturation level at 37°C in the alveolar partial pressure table, by those at 39°C and 30°C and then recalculating partial pressure figures of oxygen and carbon dioxide. The result is startling and deciphers the significance of 37°C. As of today, there is probably no place on the earth where one can have ambient air at 37°C concurrently with 100% RH. Such is the uniqueness of alveolar air parameters. Apparently this uniqueness is threatened by climate change. We are ourselves infringing on this ‘Natural Selection’. At certain places we have pushed ourselves, closer to 37°C at 100% RH, as an outcome of massive urbanization and industrialization. As a result the key critical process of humidification and conditioning of inspired air, essentially at the upper respiratory tract URT, has gone redundant. A process becomes redundant, when its primary purpose is achieved beforehand. The redundancy has weakened respiratory immune defense systems as well and allowed all viruses like Sars-Cov-2, an unchallenged access to reach alveoli and enter through ACE2 receptors. Free access meteorological data of places like Wuhan indicates that the average humidity at these places were higher than 75% and concurrently temperatures were above 30°C during later part of 2019.Wuhan acted as starting point to the pandemic, where some people had a weak or disabled immune defense due to the redundancy in upper respiratory tract (URT). Once the infections crossed a threshold, it escalated into a pandemic.At ‘Climate Change’ meets, increase in ambient temperature concurrently with rising humidity due to massive urbanization and industrialization, and increased use of water for various industrial processes, needs to be on top of the agenda. Enthalpy, a thermodynamic property of atmospheric air, becomes a good indicator of the concurrent effect of high temperature and high humidity. Enthalpy of air crossing 70 KJ/Kg level may be set as warning sign for impending viral attack.Key Words: Relative Humidity, Alveolar Air, Natural Selection, Redundancy, Wuhan, Climate Change, Enthalpy