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Environ Sci Technol

Title:		Cold temperature and biodiesel fuel effects on speciated emissions of volatile organic compounds from diesel trucks
Author(s):		George IJ; Hays MD; Snow R; Faircloth J; George BJ; Long T; Baldauf RW;
Address:		"Office of Research and Development, National Risk Management Research Laboratory, United States Environmental Protection Agency , Research Triangle Park, North Carolina 27711, United States"
Journal Title:		Environ Sci Technol
Year:		2014
Volume:		20141125
Issue:		24
Page Number:		14782 - 14789
DOI:		10.1021/es502949a
ISSN/ISBN:		1520-5851 (Electronic) 0013-936X (Linking)
Abstract:		"Speciated volatile organic compounds (VOCs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a chassis dynamometer at two ambient temperatures (-7 and 22 degrees C) operating on two fuels (ultra low sulfur diesel and 20% soy biodiesel blend) over three driving cycles: cold start, warm start and heavy-duty urban dynamometer driving cycle. VOCs were measured separately for each drive cycle. Carbonyls such as formaldehyde and acetaldehyde dominated VOC emissions, making up approximately 72% of the sum of the speciated VOC emissions ( summation operatorVOCs) overall. Biodiesel use led to minor reductions in aromatics and variable changes in carbonyls. Cold temperature and cold start conditions caused dramatic enhancements in VOC emissions, mostly carbonyls, compared to the warmer temperature and other drive cycles, respectively. Different 2007+ aftertreatment technologies involving catalyst regeneration led to significant modifications of VOC emissions that were compound-specific and highly dependent on test conditions. A comparison of this work with emission rates from different diesel engines under various test conditions showed that these newer technologies resulted in lower emission rates of aromatic compounds. However, emissions of other toxic partial combustion products such as carbonyls were not reduced in the modern diesel vehicles tested"
Keywords:		Air Pollutants/*analysis *Biofuels *Cold Temperature *Gasoline Motor Vehicles Soybeans Vehicle Emissions/*analysis Volatile Organic Compounds/*analysis;
Notes:		"MedlineGeorge, Ingrid J Hays, Michael D Snow, Richard Faircloth, James George, Barbara J Long, Thomas Baldauf, Richard W eng 2014/11/14 Environ Sci Technol. 2014 Dec 16; 48(24):14782-9. doi: 10.1021/es502949a. Epub 2014 Nov 25"