of the air stream through deionized water at a controlled
temperature. Air samples were drawn from the chamber
via nonabsorbent tubinginto a pre-evacuatingcanister
to determine VOCs. An aldehyde pump located outside
the chamber was used to draw chamber air through
samplingcartridg es to determine the concentrations of
carbonyl compounds. A Teflon tubingconnected the
chamber with a CO analyzer, a NO–NO2–NOx analyzer
and a CH4–NMHC analyzer.
Prior to the incense burning, the chamber was
conditioned for about 4 h at standard test temperature,
air exchange rate and RH. The background air samples
were collected from the chamber to assess the background
air quality. The background levels met the
requirements of ‘Large Chamber Test Protocol for
Measuring Emissions of VOCs and Aldehydes’ (US
EPA, 1999).