Wildfire and Prescribed Burn Smoke Preparedness and Indoor Air Quality in Schools: Long-Term Air Quality Monitoring in Schools

PARICHEHR SALIMIFARD, Jalil Mokhtarian Mobarakeh, C. Victoria McCrary, Sara Jones, Perry Hystad, Molly Kile, Oregon State University

     Abstract Number: 161
     Working Group: Burning Questions of Aerosol Emissions, Chemistry, and Impacts from Wildland-Urban Interface (WUI) Fires

Abstract
Exposure to wildfire smoke fine particulate matter (PM_2.5) is a public health concern. Children are particularly vulnerable to PM_2.5 because their respiratory systems are developing, and they have a higher breathing rate relative to body size. Building readiness to maintain healthy indoor air quality (IAQ) during smoke events is important in early care and education (ECE) settings where children spend extended periods of time. This community-engaged project, supported by the U.S. EPA’s Wildfire Smoke Preparedness in Community Buildings Grant Program, is implementing and evaluating scalable IAQ interventions in Oregon’s ECE settings. Interventions included deploying portable air cleaners in classrooms and common areas, conducting real-time indoor and outdoor air quality monitoring using low-cost PM_2.5 sensors, and developing customized smoke response plans. Long-term air quality monitoring data collected from this ECE demonstrated that outdoor smoke from wildfires and prescribed burns significantly impacted indoor PM_2.5 levels. We found that building and ventilation characteristics influenced indoor PM_2.5 concentrations and used indoor-to-outdoor (IO) PM_2.5 ratio to evaluate smoke intrusion into the building. Highest outdoor PM_2.5 concentrations were measured in August which corresponded to peak wildfire activity and the start of the academic school year. Despite similar PM_2.5 trends in different rooms, notable differences in maximum values and IO ratios were observed. A classroom without ventilation exhibited the highest indoor-to-outdoor (IO) ratio, while a classroom with mechanical ventilation had the lowest IO ratio. Some IO ratios exceeded 1.0, indicating possible indoor sources of PM_2.5 or inadequate ventilation and filtration. This underscores the importance of microenvironmental characteristics in smoke infiltration dynamics. It also demonstrates a strategy for enhancing resilience in the built environment by reducing PM_2.5 exposure to vulnerable populations using accessible technologies and tailored planning.