Tree bark is an interesting source for various building and furniture materials. It holds a high number of volatile components—resulting in emissions whose effects on building residents have to be considered. Spruce and larch barks were dried using different methods and prepared as loose particles and panels. The VOC (volatile organic compound) emissions after 3 and 14 days were measured in a small chamber using gas chromatography and coupled mass spectroscopy. The influence of bark type, drying method, hot pressing and time on the emissions was quantified. The total volatile organic compounds (TVOC) emissions from spruce bark were higher than those from larch bark. High-temperature treatment and time significantly decrease TVOC emissions from the investigated barks. Terpenes, aldehydes and acids were analysed in the emitting gases. The high temperatures whilst pressing panels are problematic due to furfural constitution. Its emissions and partly those of 2-octenal and acetic acid are relevant for present and upcoming evaluation schemes. Aldehydes are the critical substance when using bark in the interior and must be controlled in product development.

Indoor air quality (IAQ) was investigated in 13 newly-built, occupied timber houses on a long-term basis. The study included a comparison of the construction types timber-frame (TF) and solid wood (SF), in addition two different ventilation types, controlled vs. window ventilation, were contrasted. The emission progression of volatile organic compounds (VOCs) including formaldehyde, was recorded and compared with the subjective well-being of the residents, which was identified by use of standardized questionnaires. This was completed with toxicological assessment and repeated measurements of specific medical parameters of health indicative character. It was found that VOC-emissions were initially elevated regardless of construction and ventilation type. However, after a period of up to 8 months emissions mostly decreased to an average level. Whereas, the SW constructions released distinctly more terpenes compared to the TF houses, there was no significant difference regarding the total concentration of emitted VOCs. The use of controlled ventilation systems resulted in lower VOC-concentrations and thus in higher IAQ compared to window ventilation. From a toxicological point of view the major part of the investigated houses were unobtrusive and IAQ was considered as “high” or “satisfactory.” Residents were continuously very satisfied with their health and quality of life. This perception was confirmed by the results gained from the accompanying medical examinations, giving no indication for physical impairments.

This paper is divided into two parts: In the first part, the model room VOC measurement concept is evaluated with specimens from different construction materials in order to estimate the safety margins when using day 28 as the time point for indoor air quality assessment. Safety margins between 2 and 20 were estimated for softwood-based products. In the second part, the theoretical restrictiveness of ECA-IAQ Report 18 derivative schemes (like AgBB or NH 105) towards the indoor-related industrial production in central Europe was evaluated.

Pine wood particles were treated with effluents from the wood-board manufacturing industry or from a communal clarification plant, and the effect of these treatments on aldehyde emissions of wood material was tested. Pine wood strands were treated in the same manner and strand boards were produced from the treated material on a laboratory scale. The 28-day volatile organic compound emissions of the boards were determined in a microchamber using Tenax-TDAS/GC-MS analytics. Boards made from treated strands exhibited significantly lower aldehyde emissions compared to control boards. Analyses of microflora and of wood extractives confirmed that microbial metabolism in industrial effluents consumed unsaturated fatty acids (UFAs) present in wood. As UFAs are the source of aldehyde emissions due to auto-oxidation, the aldehyde emission was consequently reduced. A routine treatment of wood raw material with properly chosen industrial effluents may therefore be regarded as a cost-reducing and efficient method for the utilisation of industrial waste waters.

Fuel pellets are usually produced from raw materials with high lignocellulosic content like bio-mass from wood, straw etc. with a huge variety of the raw material quality grades. While high calorific value is the most desired end-product property, other product characteristics are also of interest. Gas emissions could be crucial for the subjective acceptance of pellets as "green product" and could lead to higher indoor concentrations of unwanted volatile substances if the pellets are stored inside the premises.VOC (volatile organic compounds) emissions from pellets produced from pine and spruce were evaluated at the early stages of the product lifecycle - from wood shredding through transport and storage of the freshly produced pellets. It was found out that the VOC emission profile depends on wood type and lifecycle stage. The emitted VOC belonged exclusively to the substance classes of terpenes and aldehydes. The observations showed that spruce- and pinewood based pellets differentiated mainly in their aldehyde emissions whereby pinewood based pellets emitted substantially more aldehydes. The treatment of pinewood chips with the blue stain fungus Ceratocystis coerulescens for four weeks led to a reduction in aldehyde emissions of the produced pellets with more than 80%. Thus the profile of the VOC emissions of treated pinewood based pellets was much more similar to that of spruce based pellets.

A large-scale test set-up was designed to evaluate the volatile organic compound (VOC) emissions of building materials in a real room situation but under laboratory conditions. Two model rooms (ModR) with a volume of 30 m(3) each were constructed of the wood-based building materials X-lam and OSB, respectively. Temperature and relative humidity (RH) inside the ModR were kept in a range of 21 degrees C-25 degrees C and 45%-55% RH. VOCs were collected at 13 different times over a period of 23 weeks, and the total VOC (TVOC) concentration was calculated from GC/MS data. Results were quantified as toluene equivalents (TE). In the X-lam-ModR, the TVOC concentration decreased by 64% over the whole measurement period from 115 to 41 mu g m(-3) TE. Terpenes were the most abundant substance group and accounted, on average, for 80% of the TVOC concentration. In the OSB-ModR, the TVOC concentration decreased by 72% from 443 to 124 mu g m(-3) TE. Aldehydes showed the highest concentrations, accounting, on average, for 52% of the TVOC, while 38% were terpenes. The results show that this type of test provides realistic data for the praxis.

The demand of the global economy for fossil resources needed for the production of fuel and basic chemicals is expected to exceed supply in the coming decades. Because of its heavy reliance on fossil fuels for increased efficiencies over the 20th century, the chemical industry has been particularly motivated to harness alternative raw materials, such as biomass, that are environmentally and economically sustainable. Biorefineries have provided stable, large-scale means of converting biomass into base chemicals, but until recently the main focus has been on the conversion of the mainly cellulosic fraction of edible plants into biofuels. Second- and third-generation biorefineries are striving to be more economically integrated and sustainable by utilizing raw material fractions to a greater extent and by not competing with the agriculture and food sector. The goal of this study was to evaluate the potential of kiln-dry condensate as a source for production of bio-based chemicals. The condensates of three typical European wood species were analyzed. Part 1 evaluated the volatile extractives; Part 2 concentrates on semi- and non-volatile extractives of kiln-dry condensates.

Two model rooms were constructed out of OSB and CLT and applied as a large scale test method for emissions of volatile organic compounds (VOC) from wood based building products over a period of 23 weeks. The measured VOC emissions show terpene and aldehyde emissions in both model rooms. Emissions from all identified substances declined over time to a low value. In the CLT model room terpene emissions exceeded aldehyde emissions. Terpenes declined from 65 to 11 μg m−3 (83%), whereas aldehydes declined from 28 to 5 μg m−3 (82%). In the OSB model room aldehyde emissions were higher and declined from 247 to 51 μg m−3 (79%). Terpene emissions decreased from 59 to 23 μg m−3 (61%).

In Central Europe the main species that are used for the production of sawn wood are spruce, pine, and European beech. After the sawing process, the sawn timber is technically dried to a certain moisture content by means of condensation drying. The water movement in the cellular structure, which is caused by the drying process, draws some of the extractives into solution. In the process of kiln drying, hot air evaporates the water and the dissolved extractives. Some of the water condenses on the floor and the walls of the kiln, while the rest is blown out with the steam. Therefore, condensate was taken from the bottom of the kiln as well as from the energy recovery system. A chemical analysis by means of purge-and-trap showed the presence of volatiles that could be classified as typical for the wood materials from which they originated under the conditions of high temperature and high moisture content.

Sterilized pine wood strands were treated with the ascomycete Ophiostoma piliferum (Cartapip 97 (TM)) in an attempt to reduce aldehyde emissions through degradation of aldehyde-forming precursors. Wooden boards were then produced from the treated strands by means of a laboratory press. VOC emissions of these boards were characterized and the concentrations of seven major substances were followed for a period of 28 days in Markes mu-CTE micro-chambers employing Tenax-TDAS/GC/MS analytics. Boards made from treated strands showed a highly significant (P<0.001) reduction in aldehyde emissions by 70% compared to the control boards, while differences in the monoterpene emissions were not significant (P>0.05). Wood extractives from treated and untreated strands were also analyzed by GC/MS after milling and acetone/water extraction. A marked decrease of C18 unsaturated fatty acids was detected in agreement with the reduction of aldehyde emissions, and the monosaccharides as indicators of fungal growth were depleted and stilbenes and lignans were partially degraded.

Abstract Sapstain fungi, which reduce the value of pine wood, were isolated from an industrial wood yard in north-eastern Germany. The predominant wood discolouring species on the industrial wood yard and in the forests of the investigated region was Sphaeropsis sapinea (syn. Diplodia pinea), but Ophiostoma minus was also found. These fungi were challenged with antagonistic micro-organisms in laboratory trials and in field experiments. Amongst the tested microorganisms only strains of filamentous fungi (Trichoderma sp. and Phlebiopsis gigantea) could control the sapstain fungi on pine wood blocks efficiently. Although P. gigantea was unable to inhibit stain formation completely, the wood was bleached by this fungus in later incubation stages. In two field trials, sapstain on pine wood logs was successfully retarded for a period of 10 and 12 weeks, respectively, with a white sporulating mutant of Trichoderma harzianum. Thus, the concept using filamentous fungi as antagonists against sapstain developed under laboratory conditions also proved to be valid under natural conditions in forest eco-systems.