隙間からの漏れのせいでマスクのエアロゾル濾過効率は
カタログスペック通りにはならない

サージカル・布では12.4%・9.8%
KN95・R95では46.3%・60.2%
密着できてないKN95では3.4%

Experimental investigation of indoor aerosol dispersion and accumulation
in the context of COVID-19: Effects of masks and ventilation
https://aip.scitation.org/doi/10.1063/5.0057100
>The results show that a standard surgical and three-ply cloth masks,
>which see current widespread use, filter at apparent efficiencies of
>only 12.4% and 9.8%, respectively. Apparent efficiencies of 46.3% and 60.2%
>are found for KN95 and R95 masks, respectively, which are still
>notably lower than the verified 95% rated ideal efficiencies.

>while a loose-fitting KN95 provides a negligible apparent filtration efficiency (3.4%).