Deep Investigation of Ultrafine Particles in Urban Air

This work describes the results of a study which started in 2007 to investigate the ultrafine particle (UFP) pollution in the urban area of Rome. The sampling site was located in a street with high density of autovehicular traffic, where measurements have shown that carbonaceous particulate matter represented an important fraction of aerosol pollution. UFPs have been classified by means of an electrostatic classifier. Monodisperse aerosol was either counted by ultrafine water-based condensation particle counter or sampled by means of a nanometer aerosol sampler. Samples collected were investigated using energy filtered transmission electron microscope in combination with energy dispersive X-ray spectroscopy and electron energy loss spectroscopy. Electron transmission microscope observations revealed that carbonaceous UFPs were present also as nanotube related forms. The rapid evolution of aerosol from autovehicular exhaust plumes was observed by highly time-resolved aerosol size distribution measurements.