density of humid air

[JGinniver@AOL.COM]

Just for information, there is a useful table of the density of ambient air 

on Page 18 of Kay & Laby, table of physical and chemical constants.



This includes a table of density fo ambient air with 50% rel humidity and 

0.04% CO2 by volume, this gives the density for different air pressures and 

temperatures.



There is also a second table of corrections for humidity for values between 

20 and 80% and 10, 20 and 30 deg C these correction values are to be applied 

against the table for 50% relative humidity.   These clearly show that as 

humidity decreases from 50% the air becomes more dense, and as the humidity 

increases above 50% the air becomes less dense.



On page 19 there is also an expression provided for the densitry of moist air 

as recommended by an international working group of the International Bureau 

of Weights and measures.



Plain text is never very good for reproducing equations so if anyone would 

like a copy I will scan it and send it as a pdf file on request.



Regards,

Julian