Table 2.

Source-control factors and improvement in source control for viral RNA in total exhaled breath aerosol.

	N95	KN95	Cloth	Surgical
N95	98 (97–99)a	94 (<10−15)b	87 (<10−7)	93 (<10−15)
KN95		71 (59–79)	−120 (0.014)	−12 (0.61)
Cloth			87 (77–92)	49 (0.027)
Surgical				74 (65–81)

^aSource-control factors (SCF%) are shown in italics on the diagonal (95% confidence interval). They are defined as a percentage reduction in viral load released into the environment when wearing a mask, computed from the outward leak fraction (i.e., masked/unmasked viral load): $SCF=(1-\frac{masked}{unmasked})\ast 100$ .

^bThe improvement (%) compares row versus column as percentage increase or decrease (p-value). Statistically significant (p < 0.05) changes are shown in bold. They are defined as the relative efficacy of one mask type in source control compared to the other, computed from the ratio of outward leak fractions: $Improvement(\%)=(1-\frac{\frac{masked1}{unmasked1}}{\frac{masked2}{unmasked2}})\ast 100$.