In an atmosphere above 40%RH, expelled droplets retain their moisture content, are heavier and less able to remain airborne. Furthermore, the dissolved salts inside the remaining airborne droplets create a hostile environment for any suspended microbes, decreasing their infectious nature and any risk they pose to health.
濕度高於40% rh打擊空中感染by reducing the quantity of microbes in the air and inhibiting their infectious capability.
In humidity above 40% supersaturated solutes in the infectious aerosols inactivate the microbes and protect us from infections. The water containing droplets settle faster and have shorter "floating time" than in lower humidity atmospheres.
Below 40%RH infectious droplets lose their water content and become “dry aerosols”. Microbes get incorporated in the dry structures of the solutes, are preserved and remain infectious for longer. "Floating time" and the number of microbes is increased, compared to atmospheres with a humidity greater than 40%RH.
Scientific evidence relating to humidity and airborne infection