Critical analysis of a school district-wide response to addressing indoor airborne disease transmission

This study evaluates the efforts of Oregon’s largest school district to improve indoor air quality and mitigate airborne disease transmission in the wake of the COVID-19 pandemic. We assess compliance with ASHRAE Standards 241 and 62.1 , as well as the district’s stated goal of 6 equivalent air changes per hour, and examine the role of portable air cleaners (PACs) in addressing ventilation deficits. Data from a district-wide assessment of room-level airflows are used to evaluate compliance across space types, with classrooms as the central focus. We also explore whether socioeconomic status (SES) and demographic indicators are associated with differences in per-person ventilation at the school level. Across the district, 27 % of classrooms meet Standard 62.1 outdoor air requirements and 11 % comply with Standard 241 prior to PAC deployment. Modeling of the district’s PAC allocation shows that increased clean airflow raises Standard 241 compliance to 31 % of classrooms. We analyze hypothetical redistribution scenarios based on experimentally determined PAC clean air delivery rates and clean air needs, finding that such approaches could increase compliance to 89 %. Schools serving higher percentages of students with disabilities have higher median per-person classroom ventilation rates, while no statistically significant differences are associated with school-level SES or race/ethnicity distributions. Findings demonstrate the importance of setting quantitative clean airflow goals at the room level, making baseline ventilation measurements to inform PAC allocation, verifying PAC performance and noise metrics, maintaining accurate infrastructure inventories, and refining clean airflow requirements to address the complexity of school spaces.