Hi Dan, Great summary! Though within the limitations you describe, and pertaining to virulent airborne pathogens with high infectivity, such as SARS-CoV-2 as the example we are discussing. With many other pathogens and mechanisms for pneumonia, I think the pathology is more complicated and dependent upon both the features of the pathogen interacting with the host's impaired ability to ward off the infection--where normal ventilation alone is not likely to contribute meaningfully.