If you look at the supplemental figure S1 here: https://advances.sciencemag.org/content/suppl/2020/08/07/sciadv.abd3083.DC1/abd3083_SM.pdf https://advances.scie

If you look at the supplemental figure S1 here: https://advances.sciencemag.org/content/suppl/2020/08/07/sciadv.abd3083.DC1/abd3083_SM.pdf https://advances.sciencemag.org/content/suppl/2020/08/07/sci... You'll see that the N95 exhibit an order of magnitude greater reduction than surgical (99.9% vs 99% reduction against no mask baseline). Whether this practically matters, I don't know. If surgical masks are much cheaper/easier to manufacture, then I concede that those should be the focus. However, my point still half stands. Most cotton masks perform poorly. If AA was basing this policy on empirical effectiveness, they would ban those before valved N95.