To my way of thinking, we need an additional Robert Britt explainer:

* $130 CO2 meters & measuring indoor air safety

https://steveraney.medium.com/six-deadly-covid-transmission-myths-11f1038eb81e

* Mitigating stagnant indoor air: It's like smoke, recirculation, MERV-13, air changes per hour, big vs. small particles, Guangzhou (or other) case study, 2 outdoor cases & 7,232 indoor out of 7,234 cases. https://youtu.be/u6L62Zx4dkU

HVAC should be #2 priority after masks.

It's worth watching Kim Prather and Linsey Marr battle the forces of ignorance on Twitter. Marr just testified to a Congressional Committee.