Referring to the illustrated psychrometric chart, if the dry bulb temperature is 70F and the relative humidity is 40%, what is the absolute humidity? GS-RA-22 Illustration GS-RA-22: the U.S. Coast Guard has not released this illustration.

Correct Answer: Option B — 45 grains of moisture per pound of dry air

Psychrometric evaluations require locating the intersection of the 70F dry-bulb temperature line and the 40% relative humidity curve. Following the horizontal specific humidity line to the vertical axis reveals an absolute moisture content of approximately 45 grains per pound.