For that study a mass balanced model is applied to determine area-specific emissions rates in office buildings. Sources of VOCs were identified, put into 3 broad categories and quantified : building materials (23.7 %), ventilation systems (39.0 %) and occupants and their activities (37.3 %) .
A study on the identification and quantification of sources of VOC's in 5 air-conditioned Singapore office buildings
Building and Environment, Vol. 39, Issue 2, February 2004, pp 165-177