On-road Heavy-duty Vehicle Emissions Monitoring System

• Published in: Environmental science & technology 2015-02, Vol.49 (3), p.1639-1645
• Main Authors: Bishop, Gary A, Hottor-Raguindin, Rachel, Stedman, Donald H, McClintock, Peter, Theobald, Ed, Johnson, Jeremy D, Lee, Doh-Won, Zietsman, Josias, Misra, Chandan
• Format: Article
• Language: English
• Subjects: Air Pollutants - analysis; California; Environmental Monitoring - methods; Filters; Los Angeles; Models, Theoretical; Monitoring systems; Motor Vehicles; Nitrogen; Nitrogen Oxides - analysis; Reliability; Reproducibility of Results; Soot; Vehicle emissions; Vehicle Emissions - analysis; Vehicles
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es505534e

The introduction of particulate and oxides of nitrogen (NO x ) after-treatment controls on heavy-duty vehicles has spurred the need for fleet emissions data to monitor their reliability and effectiveness. The University of Denver has developed a new method for rapidly measuring heavy-duty vehicles for gaseous and particulate fuel specific emissions. The method was recently used to collect 3088 measurements at a Port of Los Angeles location and a weigh station on I-5 in northern California. The weigh station NO x emissions for 2014 models are 73% lower than 2010 models (3.8 vs 13.9 gNO x /kg of fuel) and look to continue to decrease with newer models. The Port site has a heavy-duty fleet that has been entirely equipped with diesel particulate filters since 2010. Total particulate mass and black carbon measurements showed that only 3% of the Port vehicles measured exceed expected emission limits with mean gPM/kg of fuel emissions of 0.031 ± 0.007 and mean gBC/kg of fuel emissions of 0.020 ± 0.003. Mean particulate emissions were higher for the older weigh station fleet but 2011 and newer trucks gPM/kg of fuel emissions were nevertheless more than a factor of 30 lower than the means for pre-DPF (2007 and older) model years.