Sources and concentrations of volatile organic compounds in Bangkok office buildings

Abstract

The study objectives were to measure concentrations and to determine sources of 13 VOCs in 17 office buildings with air conditioning systems in Bangkok. Air samples were collected on Tenax-TA sorbent tubes and analyzed by thermal desorption-gas chromatography / mass spectrometry. Building ventilation was measured with a constant injection technique using hexafluorobenzene as a tracer gas. The results show that the VOC concentrations varied significantly among the studied buildings. The most two dominant VOCs were toluene and limonene with the average concentrations of 110 and 60.5 μg m -3 , respectively. Mean indoor and outdoor concentration ratios of the aromatic compounds and limonene ranged from 2.9 to 11.6, implying that indoor sources are important factor. The mean ventilation rate for the study buildings was 0.29 h -1 or 0.73 m 3 h -1 m -2 , which was lower than the suggested value of 2 m 3 h -1 m -2 by the Thai legislation for ventilation control of special large buildings.