Table 1:

Performance metrics used in this study. Outward mask airflow is in the direction of exhalation. Inward airflow is in the direction of inhalation.

Performance metric	Parameter measured	Mask airflow direction	Measurement instrument	Measurement method	Particle size	Instrument airflow rate (liters/minute)
Cough aerosol collection efficiency	Aerosol mass escaping beyond mask into collection chamber	Outward	Andersen impactor	Fluorescence of aerosol on impactor stages	0.1 to 7 μm	28.3
Exhaled aerosol collection efficiency	Aerosol mass escaping beyond mask into collection chamber	Cyclical	Andersen impactor	Fluorescence of aerosol on impactor stages	0.1 to 7 μm	28.3
Filtration efficiency	Aerosol mass concentration upstream & downstream of mask	Inward	TSI 8130A	Photometer	75 nm count median diameter (GSD 1.86)	85
Airflow resistance	Pressure required for 85 lpm flow	Inward	TSI 8130A	Manometer	n/a	85
Manikin fit factor	Aerosol particle count inside & outside mask	Cyclical	TSI PortaCount	Size classifier & condensation particle counter	55 nm (N95 mode)	0.35
Human fit factor	Aerosol particle count inside & outside mask	Cyclical	TSI PortaCount	Size classifier & condensation particle counter	55 nm (N95 mode) 0.02 – 1.0 μm (Class 100 mode)	0.35