Publication Date


Document Type


Organizational Units

Chemistry and Biochemistry


Atmospheric chemistry, Emissions, Pollutants, Heavy-duty diesel trucks


California and Federal emissions regulations for 2007 and newer heavy-duty diesel engines require an order of magnitude reduction in particulate matter and oxides of nitrogen spurring the introduction of new aftertreatment systems. Since 2008 four emission measurement campaigns have been conducted at a Port of Los Angeles location and an inland weigh station in the South Coast Air Basin of California. Fuel specific oxides of nitrogen emissions at the Port have decreased 12% since 2010 while infrared opacity (a measure of particulate matter) remained low, showing no diesel particulate filter deterioration. The weigh station truck’s fuel specific oxides of nitrogen emission reductions since 2010 (18.5%) almost double the previous three year’s reductions and are the result of new trucks using selective catalytic reduction systems. Trucks at the weigh station equipped with these systems have a skewed oxides of nitrogen emissions distribution (half of the emissions were from 6% of the measurements) and had significantly lower emissions than similarly equipped Port trucks. Infrared thermographs of truck exhaust pipes revealed that the mean temperature observed at the weigh station (225 ± 4.5°C) was 70ºC higher than for Port trucks, suggesting that the catalytic aftertreatment systems on trucks at our Port site were below minimum operating temperatures.

Copyright Statement / License for Reuse

Creative Commons Attribution-NonCommercial 4.0 International License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License

Publication Statement

This is an Accepted Manuscript for

Bishop, G. A.; Schuchmann, B. G.; Stedman, D. H. (2013) Heavy-duty Truck Emissions in the South Coast Air Basin of California, Environ. Sci. Tech. 47, 9523 - 9529. DOI: 10.1021/es401487b.

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Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman


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English (eng)


24 pgs

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136 KB