Low-Invasive CO2-Based Visual Alerting Systems to Manage Natural Ventilation and Improve IAQ in Historic School Buildings

Abstract

Children spend a large part of their growing years in schools, and as they are more sensitive to some pollutants than adults, it is essential to monitor and maximize the indoor air quality (IAQ) in classrooms. Many schools are located in historic and heritage buildings, and improving the IAQ, preserving the architectural features, poses a great challenge. The aim of the study is to evaluate the effectiveness of a low-invasiveness, low-cost, smart CO2-based visual alerting systems to manage natural ventilation and improve IAQ in historic school buildings. Indoor and outdoor parameters were monitored for three weeks in four schools with different levels of education (two classrooms per school; device installed in one only). Based on indoor CO2 concentration, air temperature and relative humidity, the device suggests when windows should be opened to ventilate. The comparison between the two classrooms show that the effectiveness of the device is highly dependent on the occupants: (i) reduction in the average CO2 concentrations of up to 42% in classrooms with frontal lesson and full occupancy, (ii) the device is not the most ideal solution for kindergarten due to the young age of the pupils, and (iii) it is more used during mild outdoor temperatures.

Determining ventilation strategies to relieve health symptoms among school occupants

“…However, this value is rarely reached as results of study containing 108 classrooms in 60 Finnish schools show that the standard level was not reached in any of the classrooms with passive stack ventilation or with mechanical exhaust only (Toyinbo et al , 2016). In addition, listed and historic buildings do not typically meet the current energy-efficiency and ventilation rate standards in their current use (Avella et al , 2021a, 2021b; Kalamees et al , 2015). This has led to installation of new ventilation systems and other changes, which have followed by building damage and led to expensive remediations and loss of historical values.…”

“…In Italy, IAQ of naturally ventilated classroom was tended to improve by using a lowcost CO 2 -based visual-alerting system. The system had a positive effect on IAQ, but its effectiveness was highly dependent on the occupants, and the system is more likely to be used with mild outdoor temperatures (Avella et al, 2021a(Avella et al, , 2021b. In Switzerland, CO 2 concentrations of naturally ventilated classrooms were remarkably reduced by the intervention in which the ventilation took place exclusively during breaks between lessons (Vassella et al, 2021).…”

CO2 and thermal comfort analysis of schools in Lugano – a wide-scale monitoring

“…Indoor CO2 measurement has been widely investigated by researchers in combination with energy saving [2]- [6], thermal comfort [1] and respiratory diseases [4]. Authors also monitored additional buildings in the previous years within the boundaries of an Interreg project [3], with interesting results in terms of air exchange frequency and CO2 trends, but there is still a margin for improvement in the connection of CO2 (and other parameters) with the actual occupation of a building: namely being able to better fine-tune systems (e.g.…”

The Control of Metabolic CO2 in Public Transport as a Strategy to Reduce the Transmission of Respiratory Infectious Diseases

“…Many countries are making high economic investments to equip schools with CO 2 meters [ 41 , 42 ]. In addition, other isolated initiatives have successfully implemented this methodology in shopping centers [ 43 ], collective transport [ 44 , 45 , 46 ], offices [ 47 ], or university and school classrooms [ 47 , 48 , 49 , 50 , 51 , 52 ]. Specifically, a recent study in Italy reported an 82% reduction in secondary COVID-19 infections in schools where they controlled air renewal from CO 2 measurements [ 53 ].…”