## 4 VOCs from Wood and Wood-Based Panels as a Potential Health Risk, Ways of their Mitigation  
Taking into account human wellbeing, the German Committee for Health-Related Evaluation of Building Products (AgBB) [105] promotes VOCs' effects from building materials ranging from unpleasant odors and irritation in the mucous membranes of the eyes, nose, and throat to effects on the nervous system and long-term effects. Substances causing allergy or aggravating allergic reactions and, most specifically, those with carcinogenic, mutagenic, or reprotoxic potential belong to this category. Therefore, AgBB has stated the so-called LCI values (Lowest Concentration of Interest) for 184 compounds such as terpen and aldehydes that usually occur in building materials concerning wood-based panels. Setting up the limit values might secure a low VOCs emission materials production. Various terpenes--alpha-pinene, beta-pinene, and hexanal--are considered irritating to eyes, respiratory system, and skin [16]. Decanal and nonanal cause irritation to eyes and skin, while furfural irritates eyes and skin and is noted for limited evidence of a carcinogenic effect. Alpha-pinene may be harmful by inhalation and in contact with skin. According to [PERSON] [106], concentrations of VOCs up to 25,000 \(\upmu\)g m\({}^{-3}\) lead to headaches and other neurotic (derogative for the nervous system) symptoms. Formaldehyde can cause eye and upper respiratory tract irritation, and moreover, it was classified as a Group 1 human carcinogen by the International Agency for Research on Cancer [13]. On the other hand, [PERSON] et al. [107] tested the impact of pine wood and OSBs VOCs' emission on human sensory irritations and found no adverse effects on the eyes, nose, throat, upper airways, or lung function after exposure to even the highest VOC levels (concentrations of up to 13,000 \(\upmu\)g m\({}^{-3}\)). Eye blink frequency as a parameter for irritation was not affected during or after exposure. Sensorial perception of odor was the only detectable effect--odor of both pine wood and OSB was considered as more \"pleasant\" than \"unpleasant\". Moreover, the study from the Institute of Health Technology and Prevention Research [108] proclaims the positive effect of Stone Pine (Pinus cembra) essential oils from furniture and cladding on human health in terms of stress inhibition, breath soothing, and heart frequency reduction leading to relaxed feelings. Since wood VOCs' presence in the indoor air is a case of concern, ways to reduce VOCs release from wood are still in demand. [PERSON] and [PERSON] [109] described the effect of thermal treatment on solid wood VOCs emission, showing an increase of about 60% at 140 \({}^{\circ}\)C compared to 120 \({}^{\circ}\)C. These findings were proven by [PERSON] et al. [61]. The thermal modification at the temperature of 60 \({}^{\circ}\)C accelerates the terpene emission and at the temperature 120 \({}^{\circ}\)C removes the terpenes almost completely. Heat treatment of spruce and pine wood significantly reduces VOCs emission and at the same time changes their composition compared to untreated or naturally air-dried wood. In particular, terpene emissions in case of spruce and pine decrease during the heat treatment process. Concerning both conifers and poplar, heat treatment leads to a reduction in hexanal emissions but evokes an increase in furfural emissions for both conifers and deciduous trees. Nevertheless, the thermal treatment can be used as a suitable method for VOCs emission mitigation, leading to a reduction of a potential health risk caused due to humans' exposure to VOCs. The heat treatment of wood makes wood a suitable and harmless material for use in indoor environments [71]. In case of wood-based materials, manufacturing parameters optimization, mainly regarding temperature and press time, reduce VOCs emission [86]. [PERSON] et al. [110] showed that the heat treatment of PB (at 50 or 60 \({}^{\circ}\)C) reduced formaldehyde and other volatiles emissions significantly.