Relationship between Exhaled Aerosol and CO2 Emission

Relationship between Exhaled Aerosol and Carbon Dioxide Emission Across Respiratory Activities

Respiratory particles produced during vocalized and nonvocalized activities such as breathing, speaking, and singing serve as a major route for respiratory pathogen transmission. 

This work reports concomitant measurements of exhaled carbon dioxide volume (VCO₂) and minute ventilation (VE), along with exhaled respiratory particles during breathing, exercising, speaking, and singing. 

Exhaled CO₂ and VE measured across healthy adult participants follow a similar trend to particle number concentration during the nonvocalized exercise activities (breathing at rest, vigorous exercise, and very vigorous exercise). Exhaled CO₂ is strongly correlated with mean particle number (r = 0.81) and mass (r = 0.84) emission rates for the nonvocalized exercise activities. 

However, exhaled CO₂ is poorly correlated with mean particle number (r = 0.34) and mass (r = 0.12) emission rates during activities requiring vocalization. 

These results demonstrate that in most real-world environments vocalization loudness is the main factor controlling respiratory particle emission and exhaled CO₂ is a poor surrogate measure for estimating particle emission during vocalization. 

Although measurements of indoor CO₂ concentrations provide valuable information about room ventilation, such measurements are poor indicators of respiratory particle concentrations and may significantly underestimate respiratory particle concentrations and disease transmission risk.

To read more click on this link: https://pubs.acs.org/doi/10.1021/acs.est.4c01717