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Emissions of wood building products will be of increased relevance in the future due to a regulation (Construction Products Regulation, CPR) as well as harmonised standardisation currently being established by the European Commission. Objective of this study was to look into the effect of four different drying schedules on volatile organic compound (VOC) product emissions from convection dried Norway spruce timber. Samples dried at high temperature initially emitted generally less VOCs compared to samples dried at low temperature. After 28 days of testing, differences were less clear. The composition of compounds was not influenced by the drying schedule, and emissions did not exceed concentrations of 300 mg m 23 . However, preliminary tests on other Norway spruce samples showed emissions up to one order of magnitude higher, mainly due to stress induced high extractives content, illustrating the variability of the amount of emitted compounds.

Acetic acid (AA) emission from beech samples was studied in test chambers operated according to ISO 16000 part 9 and as a function of temperature and relative humidity (RH). The impact of RH was higher than that of temperature. AA emission was about 45 % higher at 75 % RH than under standard parameters (50 % RH, 23 ° C). Probably, RH infl uences AA emission both by enhanced hydrolysis of acetyl groups, as well as by facilitating the release of AA into the surrounding air by diffusion. The concentration of AA in test chamber air was determined with thermal desorption-gas chromatographymass spectrometry (TD-GC-MS) as well as with ion chromatography (IC). Both techniques provided similar results. The values measured by IC ranged constantly 15 % below those obtained with TD-GC-MS. This can be ascribed to losses during sampling of test chamber air.

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