A5014731256- Vehicle emissions and performance
- Air Quality and Health Impacts
- Air Quality Monitoring and Forecasting
- Atmospheric chemistry and aerosols
- Catalytic Processes in Materials Science
- Advanced Combustion Engine Technologies
- Environmental Policies and Emissions
- Energy, Environment, and Transportation Policies
- Engineering Applied Research
- Toxic Organic Pollutants Impact
- Maritime Transport Emissions and Efficiency
- Structural mechanics and materials
- Infrastructure Maintenance and Monitoring
- Transportation Safety and Impact Analysis
- Asphalt Pavement Performance Evaluation
- Aerosol Filtration and Electrostatic Precipitation
California Air Resources Board
2011-2023
University of California, Los Angeles
2014-2017
West Virginia University
2009
California Department of Fish and Wildlife
2008
University of California, Riverside
2002-2007
Heavy-duty on-road vehicles account for 70% of all freight transport and 20% transportation-sector greenhouse gas (GHG) emissions in the United States. This study measured three prevalent GHG – carbon dioxide (CO2), methane (CH4) nitrous oxide (N2O) from seven heavy-duty vehicles, fueled by diesel compressed natural (CNG), compliant to MY 2007 or 2010 U.S. EPA emission standards, while operated over six routes used movement California. Total combined (tractor, trailer, payload) weights were...
Four heavy-duty and medium-duty diesel vehicles were tested in six different aftertreament configurations using a chassis dynamometer to characterize the occurrence of nucleation (the conversion exhaust gases particles upon dilution). The aftertreatment included four particulate filters two selective catalytic reduction (SCR) devices. All DPFs reduced emissions solid by several orders magnitude, but certain cases volatile mode could increase total particle number emissions. be predicted...
Emissions from four heavy-duty and medium-duty diesel vehicles were tested in six different aftertreatment configurations using a chassis dynamometer. The included particle filters (DPF) two prototype selective catalytic reduction (SCR) devices for NOx control. goal of the project was to fully characterize emissions various in-use meeting 2007 particulate matter (PM) standard United States California provide snapshot 2010 compliant vehicles. all worked as designed, realizing significant...
The objective of this study was to measure ammonia (NH3) emissions from modern technology vehicles since information is scarce aboutthis importantsource particulate matter (PM) precursors. Test variables included the emission level which vehicle certified, operating conditions, and catalyst age. Eight with low-emission (LEV) super-ultralow-emission (SULEV) certification levels were tested over Federal Procedure (FTP75), a US06 cycle, hot running 505, New York City Cycle (NYCC), specially...
In total, 24 polycyclic aromatic hydrocarbons (PAHs) in both gas and particle phases 35 nitro-PAHs phase were analyzed the exhaust from heavy-duty diesel vehicles equipped with after-treatment for particulate matter (PM) NOX control. The test carried out using a chassis dynamometer under highway cruise, transient Urban Dynamometer Driving Schedule (UDDS), idle operation. efficiently abated more than 90% of total PAHs. Indeed, particle-bound PAHs reduced by >99%, gaseous removed at various...
Fast-sizing spectrometers, such as the TSI Engine Exhaust Particle Sizer (EEPS), have been widely used to measure transient particle size distributions of vehicle exhaust. Recently, measured during different test cycles begun be for calculating suspended particulate mass; however, several recent evaluations shown some deficiencies in this approach and discrepancies relative gravimetric reference method. The EEPS converts electrical charge carried by particles into based on mobility...
Oxygenate content and fuel volatility (distillation) variables are important parameters affecting vehicle exhaust emissions, data on their effects the latest technology vehicles quite limited. For this study, 12 California-certified LEV to SULEV were tested a matrix of fuels with varying levels ethanol concentration (0, 5.7, 10 vol %), T50 (195, 215, 235 °F), T90 (295, 330, 355 °F). There statistically significant interactions between for NMHC, ethanol, CO NOx. NMHC emissions increased...
This study evaluated the UN-ECE Particle Measurement Programme (PMP) protocol for measurement of solid particle number emissions under laboratory and on-road conditions two passive diesel filters (DPF)–equipped medium heavy-heavy duty vehicles. The PMP were lower than European light-duty certification value (9.6 × 1011 #/mi) all standardized cycles, but exceeded this during some higher load driving conditions. measurements generally less variable those PM mass testing, had comparable or...
This study provides an evaluation of the nature sub-23-nm particles downstream European Particulate Measurement Programme (PMP) methodology, with prescribed cycles and on-road flow-of-traffic driving conditions. Particle number concentrations size distributions were measured using two PMP measurement systems running simultaneously. For this analysis, focus is on real-time results from multiple instruments. The revealed that a significant fraction both for all tested below 11 nm. sub-11-nm...
NH3 emissions from motor vehicles have been the subject of a number recent studies due to their potential impact on ambient particulate matter (PM). Highly time-resolved can be measured and correlated with specific driving events utilizing tunable diode laser (TDL). It is possible incorporate this new information into models that used predict inventories vehicles. The newer generation modal are based events, data collected at second-by-second time resolution, unlike bag-based emission...
It is important to understand the differences between emissions from standard laboratory testing cycles and those actual on-road driving conditions, especially for solid particle number (SPN) now being regulated in Europe. This study compared mass SPN a heavy-duty diesel vehicle operating over urban dynamometer schedule (UDDS) conditions. Particle were calculated using integrated size distribution (IPSD) method called MIPSD. The MIPSD UDDS tests more than 6 times lower U.S. 2007 particulate...
Particle emissions from heavy-duty vehicles (HDVs) have significant environmental and public health impacts. This study measured total particle number emission factors (PNEFs) six newly certified HDVs powered by diesel compressed natural gas totaling over 6800 miles of on-road operation in California. Distance-, fuel- work-based PNEFs were calculated for each vehicle. Distance-based equipped with original equipment manufacturer (OEM) particulate filters (DPFs) this decreased 355–3200 times...
This work evaluated the nitrogen oxide (NOx) emissions of 277 heavy-duty diesel vehicles (HDDVs) from three portable emission measurement system testing programs. HDDVs in these programs were properly maintained before testing, so malfunction indicator lamp (MIL) was not illuminated. NOx some significantly higher than certification standard even during hot operations where exhaust temperature ideal for selective catalytic reduction to reduce NOx. For engines certified 0.20 g/bhp-hr standard,...