typical outpatient setting, the required indoor #CO2 concentration at which R0 does not exceed 1 is below 620 ppm w no mask, 1000 ppm w a surgical mask and 16000 ppm w an N95 mask. In a typical inpatient setting, otoh the required indoor CO2 concentration is below 540 ppm with no mask, 770 ppm with a surgical mask, and 8200 ppm with an N95 mask. These findings facilitate the establishment of a strategy for preventing #airborne transmission in hospitals. https://pubmed.ncbi.nlm.nih.gov/37286835/#nosocomial
