Table 1.

Log kill efficacy in ozone-exposed respirator pieces compared with the controls

Respirator	Case number	Log CFUs/respirator piece (control group)	Log CFUs/respirator piece (ozone group)	Kill yield log
3M 1870	1.1	8.48	ND	>8
	1.2	9.48	ND	>9
	1.3	7.95	ND	>7
	1.4	8.00	ND	>8

Kill yield log is expressed as the base 10 logarithm of the reduction in organisms. Log 3 = 99.9%, log 6 = 99.9999%, etc. Greater than log 7 kill of Pseudomonas aeruginosa bacteria was achieved on heavily inoculated pieces of N95 masks using 400 ppm ozone for 2 hours with relative humidity 80%.

CFU, colony-forming units; ND, not detected.