A study conducted by the Joe C. Wen School of Population & Public Health has found that adding HEPA filter air cleaners to classrooms can significantly improve air quality and reduce pollution exposure for students. “Not all classrooms have the same air quality – especially in communities with lower socioeconomic status and higher minority populations, where children are often exposed to more air pollution,” said corresponding author Veronica Vieira, chair and professor of environmental and occupational health. From July 2022 to June 2023, researchers examined air quality in 17 Los Angeles Unified School District elementary schools – specifically, 186 classrooms, 99 with portable HEPA filter air cleaners and 87 with standard non-HEPA air cleaners. “Our findings were striking given that portable filters were in addition to existing HVAC systems,” Vieira said. “Classrooms with HEPA filters had 39.9 percent lower levels of … fine particulate matter and 13.8 percent to 82.4 percent less outdoor air pollution infiltrating indoors.”