# Sustainable Reduction of the Odor Impact of Painting Wooden Products for Interior Design
## 1 Introduction  
All kinds of products have an environmental impact during their life cycle, from their production to their final disposal. Product design defines more than 80% of the environmental load; therefore, sustainable choices must be made in this phase [1]. It is evident that product sustainability is a priority for European market policies which promote the decrease of hazardous chemicals and the increase of energy and resource efficiencies of products, with positive effects on the environmental footprint [2]. The building field represents one of the key sectors included in the recent European Circular Economy Action Plan, because it has been estimated that it causes about 10% of the total national greenhouse gas emissions [2]. The interior design market is strongly related to this sector since each building needs to be furnished [3]. In this regard, the wood painting shows many criticalities for its significant contribution to poor air quality and electricity consumption [3; 4; 5; 6]. Doors are typical wood components inside buildings. The door production sector involves the use of different solvent-based paints with the consequent emission of volatile organic compounds (VOCs) and odor pollutants, with effects on the environment, human health and personal welfare [7; 8]. VOCs represent an important category, since they may also be toxic at low concentrations, causing severe effects when inhaled. For these reasons, their detection is important for the assessment of indoor air quality [9; 10]. These pollutants, when emitted into the atmosphere, participate in the photochemical smog phenomena [11]. A further significant impact related to VOCs is odor emission, which often causes a strong and persistent annoyance for the population [12]. In more detail, odor is the property of a substance, or rather of a mixture of substances, capable of triggering the sensation of smell [13; 14; 15; 16]. This aspect is the subject of increasing attention for the public administration and could be translated into consent decrease and economic loss for the companies responsible. Indeed, in communities exposed to odor emissions,even though there may be no immediate apparent diseases or infirmities, there is not an atmosphere of complete mental, social, or physical wellbeing [17]. Odor emissions are considered air pollutants that require immediate attention [18; 19; 20; 21]. The World Health Organization has defined air pollution as the environmental risk with the highest mortality among developed countries, causing more than 150,000 deaths per year [22]. This has pushed the European Commission to issue directives focused on emission reduction, with a particular attention on VOCs, with reduction targets of 28% between 2020 and 2029 and 40% from 2030 in the EU area [23; 24; 25]. As a consequence of both the legislation and the circular economy pillars, companies are moving towards the development of high efficiency abatement systems and environmentally-friendly products to reduce the release of hazardous substances into the environment [26; 27]. The control of VOC (and odor) emissions can be carried out by different approaches, depending on the possible separation or destruction [16; 28; 29; 30]. The applicability of the different treatments mainly depends on the composition and the amount of the waste gases; additionally, temperature, moisture and particulate content should be considered. A combination of different treatments is often advantageous. The main approaches towards odor emission abatement include adsorption (by activated carbon, activated alumina, silica gels and zeolites), absorption, thermal oxidation, catalytic oxidation, photocatalysis, and membrane use [28; 31; 32]. Biological treatment systems mainly include biofilters and bioscrubbers/biotrickling [28; 33; 34]. Thermal treatment is one of the most common approaches; it involves the use of high temperatures (900-1000 \({}^{\circ}\)C) to oxidate VOCs to CO\({}_{2}\) and H\({}_{2}\)O and it can be applied to any exhaust air [28].