UC Riverside

This comprehensive dissertation explores the real-world emissions of heavy-duty vehicles in goods movement, focusing on regions in California. Spanning five parts, the study assesses the emissions of nitrogen oxides (NOx), black carbon, and particulate matter (PM) from diesel and compressed natural gas (CNG) vehicles, as well as the emerging role of battery electric vehicles (BEVs) in the heavy-duty sector.Chapter 2 evaluates NOx and black carbon emissions from six heavy-duty diesel and CNG vehicles in California's San Joaquin Valley and Sacramento regions. Findings reveal that CNG vehicles emit significantly lower NOx but higher black carbon than diesel vehicles equipped with diesel oxidation catalysts (DOCs) and diesel particulate filters (DPFs). The study highlights the uneven distribution of emissions across urban areas, emphasizing the higher exposure of disadvantaged communities to these pollutants. In Chapter 3, a collaboration between the University of California Riverside and CALSART under the Volvo LIGHTS project assesses emissions from 15 different diesel vehicles. The study identifies variations in emissions based on vehicle types and operational conditions. Notably, yard tractors exhibit higher brake-specific NOx and THC emissions, while Class 8 trucks show significant emissions during idling. The results underscore the need for targeted emission reduction strategies in heavy-duty diesel vehicles. Chapter 4 addresses the potential of heavy-duty BEVs in reducing emissions in the South Coast Air Basin. It compares lab and real-world performance data for BEVs, highlighting their operational patterns, energy consumption, and range. This part emphasizes BEVs as a viable solution for meeting air quality and climate goals in freight transportation. Chapter 5 focuses on the particulate emissions of diesel vehicles in the South Coast Air Basin, particularly under DPF regeneration conditions. The study finds significant emissions of ultrafine particles in disadvantaged communities, pointing to a disproportionate environmental impact. Finally, chapter 6 discusses the role of Portable Emissions Measurement Systems (PEMS) in future enforcement of in-use emissions regulations. Utilizing the University of California, Riverside's Mobile Emissions Laboratory, the study validates the accuracy of PEMS in measuring emissions under real-world conditions. Overall, this dissertation provides a detailed analysis of emissions from heavy-duty vehicles in freight transport. It highlights the disparities in emission levels based on vehicle types and technologies, the significant exposure of disadvantaged communities to pollutants, and the promising role of BEVs and PEMS in addressing these challenges. The findings are crucial for informing policies and strategies aimed at reducing emissions and protecting public health in freight-dependent regions.