Alicia Kusaka

Title: Clean Air Equity: HEPA Air Purifier Efficacy and School Report-Backs

Abstract:

The Healthy Air, Healthy Schools Project began in 2020 to better understand the impact ofportable air cleaners as an intervention in schools to reduce particulate matter of outdoor originand improve clean air equity. Populations who experience ethnic/racial and social disparitiesbear a disproportionate burden of air pollution exposure which should be considered whenplanning and implementing air quality interventions in schools. The ongoing second phase of theproject is collecting real-time air quality and HEPA air cleaner usage data across 17 participatingschools in King County, Yakima County, and Yakama Nation that serve a diverse populationincluding Hispanic youth and BIPOC youth. This report is based on the six-month preliminaryresults of 10 study schools in King County and builds on the short-term HEPA results fromPhase 1 of the study. One portable air cleaner with a HEPA (high efficiency particulate air) filterwas deployed in five classrooms at every study school. Air quality data, including PM2.5, wasrecorded inside the same five classrooms and one outdoor location at each school to measure theimpact of HEPA air cleaners. HEPA energy usage was collected with an energy logger tomonitor whether the HEPAs were used and how much they were used. The average infiltrationrate of outdoor particulate matter from February to August 2023 was 71.5% across the schoolswith observed school differences. Over the observation period, the HEPA air cleaners were used56.1% of the deployment time, though between school differences were also observed. When on,the HEPAs were 46.2% effective at reducing PM2.5 in classrooms when the outdoor PM2.5concentration was greater than 12 μg/m3, the Environmental Project Agency’s annual thresholdfor good air quality. As Phase 2 of the project continues, the study team will further analyze theeffectiveness and pattern of HEPA air purifier usage to inform recommendations on improvingair quality in schools.