(53e) How Will Modern Light-Duty Diesel Vehicles Modify CCN?

mission control technologies are globally used to mitigate air pollution from anthropogenic sources. Control technologies, such as diesel particulate filters (DPFs), efficiently filter and remove particulate mass. However, the number of ultrafine particles emitted during the regeneration of a DPF can increase by several orders of magnitude. In addition, these regenerated aerosols may have different chemical and physical composition from the original emissions source. The change in physicochemical aerosol properties during the filtering and regeneration process may greatly affect their potential to serve as cloud condensation nuclei (CCN). While the CCN activity of emissions during normal vehicle operation has been characterized, the CCN activity of aerosols derived from the regeneration of DPFs has not been investigated. This research measures the CCN activity of aerosols derived from the regeneration of DPFs. Modern light duty diesel vehicles equipped with DPFs before and during regeneration were tested on a chassis dynamometer. Real-world vehicle conditions are simulated with the highway fuel economy test cycle (HWFET). Baseline testing (non-regeneration) was completed using a federal ultra-low sulfur diesel (ULSD) over a HWFET cycle. Regeneration testing was completed over the HWFET for both a ULSD and a soy based biodiesel blend to ascertain fuel effects. Results show that both changes in fuel and the regeneration process can modify the CCN activity of vehicle emissions. The global impact of the changes in hygroscopicity will be discussed