2024 Yes School Environmental Intervention to Reduce Particulate Pollutant Exposures for Children with Asthma https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5222771/ Jhun, Iny North America Experimental Students Elementary (K-5) Particulate Matter (PM) Black carbon Filtration Respiratory symptoms Asthma Indoor air quality Environmental intervention A pilot RCT in 18 classrooms tested air cleaners for children with asthma. PM2.5 and black carbon were reduced by over 40% in intervention rooms. Modest improvements in peak flow suggest school-based filtration may reduce pollutant exposure risk. 2017