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Trends in the emissions of Volatile Organic Compounds (VOCs) from light-duty gasoline vehicles tested on chassis dynamometers in Southern California
Abstract We present fleet average VOC emission rate trends for the longest running in-use light-duty gasoline Vehicle Surveillance Program (VSP) in Southern California. Tailpipe emissions data from a limited number of vehicles tested as part of the VSP show that the 2003 fleet average emissions decreased by about 80% for most VOCs relative to the 1995 fleet. Vehicle evaporative emission rates decreased more than 90% for most compounds from the 1999 to the 2003 fleet. Tailpipe benzene-normalized emission rate ratios for most compounds were relatively stable. Evaporative emission rate ratios and weight percentages have changed significantly from the 1999 fleet to the 2003 fleet indicating a significant change in the evaporative emission species patterns. The tailpipe NMHC (Non-Methane HydroCarbon) emission reductions observed between the 1995 fleet and the 2003 fleet likely resulted from the retirement of non-catalyst vehicles in the fleets (49%) and the combined effect of the turn-over of catalyst-equipped vehicles and switch to Phase III gasoline (27%). Our results are consistent with those observed in the Swiss tunnel study. Benzene-normalized emission rate ratios for C2 compounds, aldehydes, and 1,3 butadiene are much higher in tailpipe exhaust than those in evaporative emissions. C4–C5 hydrocarbon ratios in evaporative emissions are much higher than those in exhaust. C8 aromatic compound ratios are comparable for tailpipe and evaporative emissions (hot-soak). Such ratio differences can be used to estimate the relative contributions of vehicle exhaust and evaporative emission to ambient VOCs. The contribution of emissions from malfunctioning vehicles to total fleet emissions increased from 16% to 32% for the 1995 fleet to the 2003 fleet even though the percentage of malfunctioning vehicles in the fleet decreased from 10% to 5%. Most malfunctioning vehicles are vehicles that are at least 10 years old and generally have higher acetylene emission rate ratios. The effective identification and control of these malfunctioning vehicles will become increasingly important for improving mobile source emission estimates as well as reducing future tailpipe emissions.
Highlights We present fleet trends for VOCs and NMHC from in-use light-duty gasoline vehicles. Tailpipe emission reductions come from retirement of non-catalyst vehicles (49%). VOC pattern for tailpipe emissions was stable from the 1995 fleet to the 2003 fleet. VOC pattern for evaporative emissions changed notably from the 1999 to 2003 fleet. Malfunctioning vehicles became the main contributor to the fleet total emissions.
Trends in the emissions of Volatile Organic Compounds (VOCs) from light-duty gasoline vehicles tested on chassis dynamometers in Southern California
Abstract We present fleet average VOC emission rate trends for the longest running in-use light-duty gasoline Vehicle Surveillance Program (VSP) in Southern California. Tailpipe emissions data from a limited number of vehicles tested as part of the VSP show that the 2003 fleet average emissions decreased by about 80% for most VOCs relative to the 1995 fleet. Vehicle evaporative emission rates decreased more than 90% for most compounds from the 1999 to the 2003 fleet. Tailpipe benzene-normalized emission rate ratios for most compounds were relatively stable. Evaporative emission rate ratios and weight percentages have changed significantly from the 1999 fleet to the 2003 fleet indicating a significant change in the evaporative emission species patterns. The tailpipe NMHC (Non-Methane HydroCarbon) emission reductions observed between the 1995 fleet and the 2003 fleet likely resulted from the retirement of non-catalyst vehicles in the fleets (49%) and the combined effect of the turn-over of catalyst-equipped vehicles and switch to Phase III gasoline (27%). Our results are consistent with those observed in the Swiss tunnel study. Benzene-normalized emission rate ratios for C2 compounds, aldehydes, and 1,3 butadiene are much higher in tailpipe exhaust than those in evaporative emissions. C4–C5 hydrocarbon ratios in evaporative emissions are much higher than those in exhaust. C8 aromatic compound ratios are comparable for tailpipe and evaporative emissions (hot-soak). Such ratio differences can be used to estimate the relative contributions of vehicle exhaust and evaporative emission to ambient VOCs. The contribution of emissions from malfunctioning vehicles to total fleet emissions increased from 16% to 32% for the 1995 fleet to the 2003 fleet even though the percentage of malfunctioning vehicles in the fleet decreased from 10% to 5%. Most malfunctioning vehicles are vehicles that are at least 10 years old and generally have higher acetylene emission rate ratios. The effective identification and control of these malfunctioning vehicles will become increasingly important for improving mobile source emission estimates as well as reducing future tailpipe emissions.
Highlights We present fleet trends for VOCs and NMHC from in-use light-duty gasoline vehicles. Tailpipe emission reductions come from retirement of non-catalyst vehicles (49%). VOC pattern for tailpipe emissions was stable from the 1995 fleet to the 2003 fleet. VOC pattern for evaporative emissions changed notably from the 1999 to 2003 fleet. Malfunctioning vehicles became the main contributor to the fleet total emissions.
Trends in the emissions of Volatile Organic Compounds (VOCs) from light-duty gasoline vehicles tested on chassis dynamometers in Southern California
Pang, Yanbo (Autor:in) / Fuentes, Mark (Autor:in) / Rieger, Paul (Autor:in)
Atmospheric Environment ; 83 ; 127-135
01.11.2013
9 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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