A study on the identification and quantification of sources of VOCs in 5 air-conditioned Singapore office buildings

Sources of VOCs were identified and quantified in five tropical air-conditioned office buildings in Singapore. A mass balanced model is applied to determine area-specific emission rates and to apportion the sources of VOCs into 3 broad categories of sources—building materials, ventilation systems and occupants and their activities. The highest contributor of TVOCs comes from the ventilation systems at 39.0%. This was followed by occupants and their activities at 37.3% and finally building materials at 23.7%. Ducted supply and return ventilation design has the lowest VOC area-specific emission rates as compared to buildings employing the open space above the false ceiling as return plenum. The TVOC area-specific emission rates from building materials and ventilation systems decreased from 6 to 12 months. However, some VOCs showed increased emission rates over the same period demonstrating sink effects which resulted in secondary emissions.