- Mar 27, 2012
- Reaction score
- Hendersonville, NC
People who pay attention do know. The effect is clear, reasonably well understood, and demonstrable in a number of lab experiments.there isnt any argument ovet the % they are effective, coz nobody knows, as no body knows, it be come very arguable if they reduce the spread at all, and even more arguable if this is more than insiginificant,
That you don't know is only because you ignore the evidence you don't like.