Comment by tempestn

Yes, but in that case you wouldn't be comparing 0.9005 and 0.90005, but rather 0.0005 and 0.00005. No one is arguing that the difference in filters wouldn't matter in a cleanroom context, just that recirculating air in a home the difference in filtration is more like 0.9005 vs 0.90005, and the difference between those numbers is small (in any context to which they apply).