Emissions of wooden interior materials

The use of wood in construction has increased for environmental reasons, and wood has a number of properties that are potentially beneficial for indoor environment quality and human health. However, different wood species emit a wide variety of chemical compounds, and emissions from recently dried timber in particular can be considerable. To control emissions inside buildings, some factors related to wood emissions and their relationship with human perception require deeper knowledge. This dissertation aims to provide new knowledge about the chemical emissions of wooden interior materials under specific parameters. Additionally, the performance of indoor air quality (IAQ) sensors was studied. The effects of moisture content (MC) and paints on the emissions of pinewood boards were studied in laboratory test chambers. The test specimens consisted of uncoated wood samples at two MC levels (10% and 16%), wood samples of both MCs coated with three paints, and the three paints on glass plates were used as reference samples. The emission development of the samples was studied for 28 days. Emitted compounds and their concentrations from uncoated pinewood were consistent with previous studies. Painted wood samples showed high emissions of paint-based compounds that decreased rapidly with time, while the share of wood-based compounds in the emissions increased over time. Uncoated and painted wood samples had lower emissions of wood-based compounds with higher MC (16%) resulting mainly from lower emissions of terpene compounds. Additionally, higher MC decreased emissions of paint-based compounds. The measured and perceived IAQ was studied in three low-energy wooden test buildings (TBs) with three ventilation levels. Levels of total volatile organic compounds (TVOC) were remarkably higher in test building made of pinewood timber (TB 3) than in other buildings (TB1 and TB 2) built with 'lightweight' wooden structures, and the main difference in TVOC levels was terpene concentrations. TVOC levels decreased consistently in TB 3 with higher ventilation. TVOC levels also decreased in the other test buildings, but the effect of the ventilation was less clear, especially between the two highest levels. Perceived air quality improved systematically in all test buildings with higher ventilation, and the differences between the lowest and highest ventilation levels were statistically significant. Because of the increased availability and use of sensors for monitoring TVOC levels inside buildings, performance of four metal oxide semiconductor (MOS) and one photoionization detector (PID) sensors were studied in laboratory and field experiments. Both experiments showed differences in performance between the MOS and PID sensors and between the four MOS sensors. The results suggested that current sensor technology is not capable of monitoring TVOC values precisely, but the sensors could be used to monitor temporal variations of TVOC concentrations and human-based effluents.