Ferrari S, Blázquez T, Cardelli R, De Angelis E, Puglisi G, Escandón R, Suárez R
Dept. of Architecture, Built Environment and Construction Engineering, Politecnico di Milano, Milano, Italy.
Dept. of Energy Efficiency Department, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Rome, Italy.
Heliyon. 2023 Aug 12;9(9):e19120. doi: 10.1016/j.heliyon.2023.e19120. eCollection 2023 Sep.
The importance of building ventilation in avoiding long-distance airborne transmission has been highlighted with the advent of the COVID-19 pandemics. Among others, school environments, in particular classrooms, present criticalities in the implementation of ventilation strategies and their impact on indoor air quality and risk of contagion. In this work, three naturally ventilated school buildings located in northern Italy have undergone monitoring at the end of the heating season. Environmental parameters, such as CO concentration and indoor/outdoor air temperature, have been recorded together with the window opening configurations to develop a two-fold analysis: i) the estimation of real air change rates through the transient mass balance equation method, and ii) the individual infection risk via the Wells-Riley equation. A strong statistical correlation has been found between the air change rates and the windows opening configuration by means of a window-to-volume ratio between the total opening area and the volume of the classroom, which has been used to estimate the individual infection risk. Results show that the European Standard recommendation for air renewal could be achieved by a window opening area of at least 1.5 m, in the most prevailing Italian classrooms. Furthermore, scenarios in which the infector agent is a teacher show higher individual infection risk than those in which the infector is a student. In addition, the outcomes serve school staff as a reference to ensure adequate ventilation in classrooms and keep the risk of infection under control based on the number of the students and the volume of the classroom.
随着新冠疫情的出现，建筑通风在避免空气远距离传播方面的重要性得到了凸显。其中，学校环境，尤其是教室，在通风策略的实施及其对室内空气质量和传染风险的影响方面存在关键问题。在这项工作中，位于意大利北部的三座自然通风的学校建筑在供暖季结束时接受了监测。记录了环境参数，如一氧化碳浓度和室内/室外空气温度，以及窗户开启配置，以进行两方面的分析：i）通过瞬态质量平衡方程法估算实际换气率，ii）通过威尔斯-莱利方程估算个体感染风险。通过总开口面积与教室容积之比的窗-容积比，发现换气率与窗户开启配置之间存在很强的统计相关性，该比值已被用于估算个体感染风险。结果表明，在意大利最常见的教室中，通过至少1.5平方米的开窗面积可以达到欧洲标准的空气更新建议。此外，感染源是教师的场景显示出比感染源是学生的场景更高的个体感染风险。此外，这些结果可为学校工作人员提供参考，以确保教室有足够的通风，并根据学生人数和教室容积将感染风险控制在可控范围内。
