Behavioral Changes vs. Mechanical Ventilation: the Effect of Post-COVID Measures on Indoor Environment Quality

By Alex Sun

As the Netherlands slowly reopens, the Dutch Government encourages people to take a series of measures to minimize the risk of spreading and guarantee a smooth reopening, including airing rooms and keeping social distance. We examine the effect of these post-COVID behavioral changes on indoor environment quality (IEQ) in primary schools. Primarily, we compare the IEQ performance of classrooms with and without mechanical ventilation (MV) systems to answer the question: can these behavioral changes “compensate” for the lack of MV systems?

This question can be more complex than it seems. On the one hand, if specific behaviors improve IEQ with a similar performance to that of MV systems, it provides opportunities to improve energy efficiency and save the cost of purchasing and maintaining MV systems. On the other hand, there might be a tradeoff between IEQ and thermal comfort (or probably work performance) where mechanical ventilation isn’t present—for example, airing rooms frequently during cold days.

Our initial findings show that mechanical ventilation systems have an overall performance advantage. On average, classrooms equipped with mechanical ventilation have a 5.5% lower indoor CO2 level than those without. Meanwhile, post-COVID behavioral changes significantly improved IEQ. Behavioral changes significantly improve CO2 and fine particle levels in classrooms without mechanical ventilation (7.9% decrease) than those with mechanical ventilation (1.9% decrease). However, classrooms without mechanical ventilation experienced lower indoor temperature during cold days, confirming the tradeoff between IEQ and thermal comfort.

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More findings will come as we inspect the change of IEQ minute-by-minute. We found that there are patterns in the curves that match certain behaviors. Using deep learning methods, we can identify and label these patterns and learn more about the dynamics between behavior and IEQ.

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