The influence of LEED enhanced indoor air quality credit achievement on COVID-related school closures

School closures during the COVID-19 pandemic have highlighted the importance of in-person learning on child health and wellness. Improving indoor air quality (IAQ) is a critical undertaking to keep children in school during outbreak events. Our primary objective was to evaluate the impact of Enhanced IAQ credit achievement among LEED-certified schools on the ability to remain open during the pandemic. In this analysis, schools that achieved LEED Enhanced IAQ credits for increased ventilation or outdoor air delivery monitoring were assigned to the treatment group; LEED schools without these credits were in the control group. We used LASSO regression to select potential confounders for treatment models. Inverse treatment probability weights were used to control for confounding in mixed effects Poisson models in which the response variable was the number of COVID-related school closure days during the 2021-22 academic year. Although effect estimates for the treatment were not significant, they were consistently in the inverse direction (incidence rate ratio (IRR) [95% CI]: 0.90 [0.80, 1.01]). Models may have lacked power to detect significance due to many schools having zero COVID-related closures during the 2021-22 academic year. An important secondary finding was a 53% decrease in COVID-related closure days (95% CI: 7%–77%) associated with a 10% increase in county residents who reported ‘Always’ using a mask in public. This study contributes to the current understanding of the indoor environment and airborne disease transmission. Efforts to monitor and improve IAQ in schools are important avenues to support community, student, and staff health.