Concentrations and Strengths of Formaldehyde and Acetaldehyde in Office Buildings in Bangkok, Thailand

Abstract

Exposure to aldehydes can have adverse health effects. Formaldehyde, the most abundant airborne aldehyde, is also a human carcinogen. This study investigated concentrations and strengths of formaldehyde and acetaldehyde in 12 office buildings in Bangkok, Thailand. Sampling was conducted during March and April 2008. Air samples were collected at ∼0.7—0.9 L · min—1 using cartridges filled with dinitrophenylhydrazine coated silica gel. The cartridge incorporated an ozone scrubber to prevent aldehyde losses on the silica gel surface. Samples were then desorbed by acetonitrile and analyzed by high performance liquid chromatography. Air exchange rates were estimated from the difference between indoor and outdoor carbon dioxide levels. A one-compartment mass balance model was used to estimate indoor source strengths. Results showed that the mean indoor concentrations of formaldehyde and acetaldehyde were 35.5 and 17.1 μg · m–3 respectively, while the outdoor concentra- tions were 10.1 and 7.9 μg · m–3, respectively. The estimated mean indoor strengths of formaldehyde and acetaldehyde were 15.3 and 5.8 mg · h–1, respect- ively. Indoor–outdoor (I/O) relationships showed that the I/O ratios were 3.5 for formaldehyde and 5.7 for acetaldehyde, suggesting that indoor sources are more important contributors to the indoor levels than outdoor sources such as infiltration of vehicle exhaust.