Air absorption can be approximated as an equivalent absorption area scaled to room volume.

Evidence

An approximation that seems to work is to convert the effect of the air absorption into an equivalent absorption area by scaling an air absorption coefficient by the volume of the space. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1945

Categorization

• DEFINE: Introduces ‘air absorption coefficient’ and ‘equivalent absorption area’ as workable modeling terms.