This report describes a study that assessed levels of ultrafine particles and other pollutants around diesel engine school buses and identified factors contributing to those levels. Dr. Yifang Zhu at the University of California–Los Angeles, a recipient of HEI's Walter A. Rosenblith New Investigator Award, measured pollutant levels in and around school buses while driving, while idling, before and after retrofitting with a diesel particle filter and/or oxidation catalyst, and before and after installing an in-cabin filtration system.
