The first linked study, the one from Japan, had 32 participants that finished the study and there were only 2 colds observed, one in each group. To me, a layper

The first linked study, the one from Japan, had 32 participants that finished the study and there were only 2 colds observed, one in each group. To me, a layperson, that feels like such a small sample size to be totally useless. Am I wrong about this? It's also stated, "The main transmission path is long-residence-time aerosol particles (< 2.5 μm), which are too fine to be blocked". Why when I look at a CDC article on masks does it say N95 is effective on this particle size? Unless the author is using "blocked" to mean "100% prevented from moving through the filter", which would be a higher standard than N95 masks claim to have. https://blogs.cdc.gov/niosh-science-blog/2009/10/14/n95/ https://blogs.cdc.gov/niosh-science-blog/2009/10/14/n95/