2016 Yes https://onlinelibrary.wiley.com/doi/10.1111/ina.12308 van de Zee, S.C. Europe Observational Middle/Jr High (6-8) High School (9-12) Ventilation rates Filtration Particulate Matter (PM) Ventilation Filtration Particulate matter (PM) Black carbon Highway School During teaching hours, the filter reduced BC exposure by, on average, 36%. For PM10 and PM2.5, a reduction of 34% and 30% was found, respectively. This implies that application of a fine filter can reduce the exposure of schoolchildren to traffic exhaust at hot spot locations by about one-third.