Eichholtz Piet, Kok Nils, Sun Xudong
School of Business and Economics, Maastricht University, Tongersestraat 53, 6211 LM Maastricht, The Netherlands.
PNAS Nexus. 2023 Dec 20;3(1):pgad429. doi: 10.1093/pnasnexus/pgad429. eCollection 2024 Jan.
The recent COVID-19 pandemic has made people acutely aware of the importance of indoor air quality (IAQ) and building ventilation systems, particularly in densely occupied places like offices and schools. As a result, governments and other public entities are increasingly investing in the installation, maintenance, and upgrades of ventilation systems in public buildings. However, little is known about the effect of building ventilation systems on actual IAQ and its impact on occupant behavior. This paper exploits exogenous closing and opening events of schools during the COVID-19 pandemic, combined with policy measures focusing on maximizing ventilation rates inside classrooms, to assess the effectiveness of building ventilation systems in primary schools. We use a unique sensor network implemented before the COVID-19 pandemic, consisting of measurement devices installed in 252 classrooms across 27 Dutch primary schools, continuously monitoring IAQ indicators such as CO levels and fine particle concentrations. Using high-frequency data from 2018 to 2022 school years, we compare the IAQ differences between natural and mechanical ventilation through a fixed-effect identification strategy. Our results show that mechanically ventilated classrooms perform better with respect to CO and fine particle levels. However, the post-COVID-19 ventilation measures implemented after school reopening had stronger effects on naturally ventilated (NV) classrooms, suggesting behavioral changes at the classroom level. We also investigate the longer term effects of these post-COVID-19 ventilation measures and show some evidence of decay in effectiveness, as well as a strong seasonal effect, particularly in NV classrooms, which seems the result of a trade-off between ventilation and thermal comfort.
近期的新冠疫情让人们深刻意识到室内空气质量（IAQ）和建筑通风系统的重要性，尤其是在办公室和学校等人员密集场所。因此，政府和其他公共实体越来越多地投资于公共建筑通风系统的安装、维护和升级。然而，对于建筑通风系统对实际室内空气质量的影响及其对居住者行为的影响，我们知之甚少。本文利用新冠疫情期间学校的外生关闭和开放事件，结合旨在最大限度提高教室内通风率的政策措施，来评估小学建筑通风系统的有效性。我们使用了一个在新冠疫情之前实施的独特传感器网络，该网络由安装在荷兰27所小学的252间教室中的测量设备组成，持续监测一氧化碳（CO）水平和细颗粒物浓度等室内空气质量指标。利用2018至2022学年的高频数据，我们通过固定效应识别策略比较自然通风和机械通风之间的室内空气质量差异。我们的结果表明，在一氧化碳和细颗粒物水平方面，机械通风的教室表现更好。然而，学校重新开放后实施的新冠疫情后通风措施对自然通风（NV）教室的影响更强，这表明在教室层面出现了行为变化。我们还研究了这些新冠疫情后通风措施的长期影响，并显示出有效性下降的一些证据，以及强烈的季节效应，特别是在自然通风教室，这似乎是通风与热舒适度之间权衡的结果。
