Technology innovation and assessment for clean transportation and community health
Hybrid-diesel electrical technology, alternative fuels, diesel retrofit—on-board measurement and quantification of size-resolved particle number emissions from alternative vehicle/engine/fuel technologies.
Ultrafine and nano particles (which account for over 90% of the number-based PM concentrations, but negligible mass) have been linked to more adverse human health effects than larger particles of identical composition, future regulatory changes will likely include not only the PM mass emissions criteria but also a criterion for the number of particles as a function of particle size. However, there is little fundamental data and knowledge about the relationships between particle number emissions and vehicle operating mode (e.g., cruise, idle, acceleration, deceleration), especially for diesel vehicles, new transportation technologies and alternative fuels that will be used for upgrading the existing fleets. The characteristics of vehicular particle emissions are changing rapidly through changes in vehicle fleets, technologies, fuels, and other factors. This line of my research has aimed to generate experimental data and fundamental knowledge of PM number emissions from various transportation technologies in disaggregate form, and to develop and evaluate novel vehicular PM number emissions modeling tools with high temporal and spatial resolution based on on-board vehicle emissions and operations measurements. My study on diesel particle number emissions is cutting edge and unique in four ways: (i) the on-board testing instruments collect real-time size-resolved particle number emissions which are more significant determinants of adverse health effects than the total mass of particles emitted; (ii) the emission data is collected at high temporal resolution which allows disaggregated transient modal emissions modeling; (iii) the study uses USB hardware adapter to collect engine and vehicle operating data at high temporal resolution; and (iv) the study establishes fundamental understanding of relationships between PM number emissions and vehicle/engine operating modes using robust statistical methods for the estimation of PM number emissions under real-world driving conditions. Real-world measurement and characterization of particulate matter (PM) emissions from transportation sources has significant public health implications and is a critical and timely topic in transportation systems engineering. My work on diesel particle number emissions provides a scientific and methodological base for PM number emissions quantification and regulation.