Population studies show that the use of masks either resulted in an increased incidence of
COVID-19 or had no impact.
None of the examined jurisdictions experienced decreased incidence of COVID-19 after the introduction of mask mandates, except two that had already begun a sharp descent in COVID-19 cases weeks earlier.
Two physical mechanisms are proposed to directly contribute to this finding, based on current available research. The first is scatter mechanics of dispersed respiratory droplets becoming aerosolized on collision with the mesh of a mask on outward exhalation and then lingering in air. The second is the pressurized and distant peripheral jets of unfiltered exhaled aerosol from the nozzled edges of a mask.
These phenomena result in viral particles lingering longer and traveling farther in airspace from
a masked person than exhaled respiratory droplets falling close to the body from the orifices of
an unmasked person.
There are also chemical mechanisms for increased COVID-19 cases in masked populations. This is likely due to immune suppression caused by hypoxic and hypercapnic conditions, as well as acidotic, immobilized cilia in the lungs, and reduced skin surface available to sunlight for vitamin D production.
Caution is therefore urged against use of masks among those who wish to reduce the risk, either for themselves or others, of infection with SARS-CoV-2 or COVID-19 disease.
