Relative humidity can be calculated if you know dewpoint and temperature - by formulae such as the August-Roche-Magnus approximation.
All methods - all formulae - ignore vapor resistance (perms).
Surely scientists/engineers have a way to then, as a subsequent step, bring vapor retarders into...
Thanks - pressure does matter to some of the other parameters on a psychrometric chart, but not to relative humidity. Cool - that sufficiently answers my question. Thanks.
Thanks. The section on "How much moisture can the air "hold"?" was very interesting (to me). I should perhaps have stated that I know how to calculate relative humidity at sea level. I'm trying to factor atmospheric pressure into that calculation. Although it's possible I missed an indirect...