## 1 Introduction  
With European citizens spending 90% of their time indoors, mostly in work environments, there is a growing concern regarding the impact of indoor environmental quality (IEQ) on occupants' overall comfort and well-being [1, 2]. Several studies already highlighted the adverse effects of poor IEQ on occupants' health and productivity in offices. For instance, [PERSON] et al. [3] conducted a cross-sectional study, monitoring temperature, humidity, and IAQ, and collecting survey responses from workers. The study revealed significant correlations between upper respiratory symptoms and higher indoor temperature and particle concentrations. Similarly, [PERSON] et al. [4] investigated the impact of intelligible speech, room temperature, and air supply on 65 participants in an open-plan office. Results showed reduced performance, particularly in working memory tasks, increased mental workload, cognitive fatigue, and symptoms in adverse conditions. Assessing IEQ involves a comprehensive evaluation of thermal, visual, acoustic, and indoor air quality (IAQ) domains [5]. Regarding IAQ, the identification and the quan tification of hazardous air pollutants, such as benzene, formaldehyde, carbon monoxide, carbon dioxide, and nitrogen oxides, play a key role in assessing human exposure and risk [6; 7]. Several studies reveal that indoor environments can be even twice polluted than outdoor [8], with pollutants deriving both from outdoor sources, e.g., vehicular traffic and industrial activities, as well as from indoor sources, e.g., combustion sources, building materials, furnishings, and products for household cleaning [9; 10]. A poor IAQ may lead to the onset of the Sick Building Syndrome (SBS), which the World Health Organization (WHO) defined firstly in 1983 as the medical condition in which people in a building suffer from symptoms of illness or feel unwell for no apparent reason [11]. The symptoms, which may include headache, tiredness, and throat irritation, depend on the time spent inside the building and tend to disappear once people leave. In addition to IAQ, also inadequate levels of temperature, humidity, ventilation, and illuminance contribute to the raising of SBS symptoms [12]. Furthermore, indoor soundscape has recently garnered significant attention, with efforts aimed at creating spaces that not only meet basic standards but also enhance health and well-being [13]. To sum up, a multi-domain approach is required to assess the impact of IEQ on occupants' health, comfort, and work productivity [14; 15; 16]. Thanks to the widespread adoption of Internet of Things (IoT) technology, the assessment of environmental conditions has evolved from the use of expensive data loggers for in-field measurements to the use of low-cost wireless-connected monitoring devices [17; 18]. Such a trend is evident across various applications. For instance, a low-cost IoT platform was proposed in [19], which can be applied in several acoustic monitoring scenarios, such as monitoring ultrasonic bat calls and audible wildlife vocalizations. Similarly, in the acoustic domain, ref. [20] discussed the GAIA project for monitoring noise levels inside school buildings, showcasing dedicated applications developed to aid students and teachers in accessing sensor data. The feasibility of using open-source hardware was explored in [21], focusing on energy monitoring in school buildings and demonstrating its scalability, responsiveness, and adaptability to various application requirements. Additionally, citizen engagement concerning outdoor air quality through a low-cost IoT platform was examined in [22], enabling pervasive and distributed monitoring systems. As far as indoor environmental quality is concerned, monitoring devices are typically equipped with a dozen sensors, including, but not limited to, temperature, relative humidity, illuminance, carbon dioxide, and formaldehyde. Recorded data are then transferred to ad hoc cloud software platforms via wireless networks.