# Noise Impact Analysis of School Environments Based on the Deployment of IoT Sensor Nodes
## 4 Discussion
Moreover, the nature of the technology used and the design followed sustain a flexible IoT architecture that could be easily expanded and cover buildings that do not support Wi-Fi access to the internet via LoRa communication protocols. Extensions could be performed both in size and in functionality. Furthermore, the IoT sensors support development boards that easily integrate other environmental sensors (e.g., CO\({}_{2}\) sensors, NO\({}_{2}\) sensors, etc.) or actuators, which eventually respond to relevant events depending on the values. For instance, in a human gathering area (classroom, waiting area, etc. ), the levels of carbon monoxide (CO) can be measured, and when they exceed a limit, the windows or ventilation automatically open (e.g., HVAC systems). Also, an alarm could be added to the implemented network to display a notice when the noise exceeds a limit, according to the relevant WHO recommendations and guidelines. It should be noted that the buildings where the network was installed had been energy upgraded recently during the year 2022 [30] in order to reduce their energy footprint. Teachers and auxiliary staff have noticed the produced result in the sense that there is a significant improvement in the environmental working conditions after this upgrade. Since \begin{table}
\begin{tabular}{c c c c} \hline \multicolumn{4}{c}{**Comparison of Key Points Between Studies in [4; 5; 6] and the Current Work**} \\ \hline
**Key Point** & [4] & [5] & [6] & **This Work** \\ \hline \multirow{7}{*}{_Location within_} & \multirow{7}{*}{Roadside, inside the school yard and inside the (unoccupied classroom, occupied classroom, occupied classroom, occupied classroom, occupied classroom, school yard} & The sensors inside the classrooms & The sensors were installed & The sensors were installed \\  & & & minutes per condition or & classrooms & at a certain \\  & & & condition or & above head & height in the \\  & & & & \\  & & & & \\  & & & & \\  & & & & \\  & & & & \\  & & & & \\ \hline \multicolumn{4}{c}{_IoT Infras-tructure_} & \multirow{2}{*}{No} & \multirow{2}{*}{No} & \multirow{2}{*}{Noise levels in} & \multirow{2}{*}{
\begin{tabular}{c} breaks outside \\ the offices of \\ the teachers, \\ varying on \\ \end{tabular} } \\  & & & & & \\  & & & & \\  & & & & \\  & & & & \\  & & & & \\  & & & & \\  & & & & \\ \hline \multicolumn{4}{c}{_Findings_} \\  & & & & & \\  & & & & \\  & & & & \\  & & & & \\  & & & & \\  & & & & \\ \end{tabular}
\end{table} 
Table 13: _Cont._the energy upgrading of school buildings continues in Greece, not only could the deployed IoT infrastructure assess this upgrade, but also it can measure the noise isolation level. Specifically, it could assist during the upgrades to improve noise immunity. The high level of noise is an issue of concern among all teachers in secondary and primary education, which is considered to be particularly important in the case of an explosion over a long period. The data we have collected revealed that many times during the working day, the level of noise goes beyond the upper limits set by national and EU legislation and WHO recommendations. The noise recording sensor network installation, piloted in some school complexes, would help systematically record and lead to actions to mitigate the noise through the facilitation of proper insulation installations. To this end, this could identify the magnitude of the problem and create a \"noise map\" to design and implement interventions to address it. Definitely an interdisciplinary collaboration among teachers, engineers, and municipality authorities could boost the adoption of strategies for noise mitigation in schools, resulting in beneficial learning environments. These noise reduction strategies could include campaigns to deploy soundproofing materials during energy upgrade processes, the addition of plants in certain positions indicated by specialists, and the interior redesign of classrooms and teachers' offices [2,3,15].