File Exchange

image thumbnail

Air density calculation

version (1.15 KB) by Jose Luis Prego
This function calculates the density of the air


Updated 05 Feb 2007

No License

This function calculates the air-density based on the papers:

1)'Equation for the Determination of the Density of Moist Air'
P.Giacomo, Metrologia 18, 33-40 (1982)

2)'Equation for the Determination of the Density of Moist Air'
R.S. Davis Metrologia 29, 67-70 (1992)

t = ambient temperature (ºC)
hr = relative humidity [%]
p = ambient pressure [Pa]

ver 1.0
06/10/2006 Jose Luis Prego Borges
Sensor & System Group, Universitat Politecnica de Catalunya, Spain

Cite As

Jose Luis Prego (2020). Air density calculation (, MATLAB Central File Exchange. Retrieved .

Comments and Ratings (10)

Excellent! Easy to use and well developed and cited!


missing the temperature and pressure limitations for this function?

I tried to use it to get air density in a simulation of a combustion engine with 1>=hr>=0, but it seems that after 3.5e6Pa and 1500K the function doesn't work. It returns negatives densities. I guess thats the limitations, just so it is here.

other wise great function :D

riva wahyudi

good for reference tehnical specification

riva wahyudi


paramust juntarakod

thank you for your work

Niclas -

Good work! Although the difference is minor, the correct conversion between degrees Celsius and Kelvin is:

t90 / °C = T90/K - 273.15

Check the ITS-90 page on:

Best regards,

Nanthakarn Udomputtisit

Jos x

Why not vectorize it so you can put in a list of numbers? (simply use .* instead of * etc.)
Why is f0 in the argument list?
The help should mention what "ro" is and in what units it is expressed.
End the calculations with a semi-colon to suppress the display.
For some (most) values ro is negative? Can that be true?
You should check for unphysical inputs (e.g., hr>100%).


New vectorized version 1.1
Thank's to:
Dr. Richard P. Signell
USGS, 384 Woods Hole Rd.
Woods Hole, MA 02543-1598

MATLAB Release Compatibility
Created with R13
Compatible with any release
Platform Compatibility
Windows macOS Linux