Trial reportJournal of exposure science & environmental epidemiology2025
Classroom air quality in a randomized crossover trial with portable HEPA air cleaners.
Trial report in Journal of exposure science & environmental epidemiology, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
4 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Indoor air quality in day-care centers, kindergartens, and primary schools: a pediatric health-oriented operational framework aligned with European and U.S. IAQ standards.Frontiers in pediatrics · 2026Pooled it
- Air Purifier Intervention for Respiratory Viral Exposure in Elementary Schools: A Secondary Analysis of a Randomized Clinical Trial.JAMA network open · 2025Trial
- Ambient aromatic hydrocarbons and prostate cancer: mechanistic evidence linking benzene and PAH exposure to tumor progression.Frontiers in cell and developmental biology · 2026Review
- Evaluating air cleaner effectiveness in schools: a comprehensive review and protocol of a cluster-randomized controlled trial of physicochemical and microbial markers.Frontiers in public health · 2026Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundChildren living in communities with lower socioeconomic status and higher minority populations are often disproportionately exposed to particulate matter (PM) compared to children living in other communities.
objectiveWe assessed whether adding HEPA filter air cleaners to classrooms with existing HVAC systems reduces indoor air pollution exposure.
methodsFrom July 2022 to June 2023, using a block randomized crossover trial of 17 Los Angeles Unified School District elementary schools, classroom PM concentrations were monitored and compared for 99 classrooms with HEPA filter air cleaners and 87 classrooms with non-HEPA filter air cleaners.
resultsIn HEPA classrooms, average school-year PM IMPACT: Few studies have examined HEPA filtration in a classroom environment, and this is one of the first studies since the COVID-19 pandemic to assess PM exposure in the classroom. Using a well powered block randomized crossover trial, we showed that adding portable HEPA air cleaners to classrooms that already had HVAC systems with MERV 13 air filters resulted in lower measurable PM concentrations and less infiltration of outdoor PM
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Registered trials
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