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.

[1]  Asif Weaver Christopher S. Walsh Michael P. Faiz,et al.  Air Pollution from Motor Vehicles: Standards and Technologies for Controlling Emissions , 1997 .

[2]  Min Shao,et al.  Comparison of air pollutant emissions among mega-cities , 2009 .

[3]  J. A. de Gouw,et al.  Determination of urban volatile organic compound emission ratios and comparison with an emissions database , 2007 .

[4]  D. Petrea.  Emissions of Non-Methane Volatile Organic Compounds (NMVOC) from Vehicular Traffic in Europe , 2007 .

[5]  Allen H Goldstein,et al.  Diurnal and seasonal variability of gasoline-related volatile organic compound emissions in Riverside, California. , 2009, Environmental science & technology.

[6]  Johannes Staehelin,et al.  Large decrease of VOC emissions of Switzerland's car fleet during the past decade: results from a highway tunnel study , 2005 .

[7]  Hilary R. Hafner,et al.  Source apportionment of VOCs in the Los Angeles area using positive matrix factorization , 2007 .

[8]  G. Bishop,et al.  A decade of on-road emissions measurements. , 2008, Environmental science & technology.

[9]  S. Tejada,et al.  Volatile organic compound emissions from 46 in-use passenger cars. , 1987, Environmental science & technology.

[10]  A M Winer,et al.  Effects of fuel type, driving cycle, and emission status on in-use vehicle exhaust reactivity. , 1998, Journal of the Air & Waste Management Association.

[11]  R. Baldauf,et al.  Criteria and Air-Toxic Emissions from In-Use Automobiles in the National Low-Emission Vehicle Program , 2005, Journal of the Air & Waste Management Association.

[12]  C. Weaver,et al.  Air pollution from motor vehicle , 2013 .

[13]  Yuval,et al.  Revealing source signatures in ambient BTEX concentrations. , 2008, Environmental pollution.

[14]  C. Koshland,et al.  Evaluation of combustion by-products of MTBE as a component of reformulated gasoline. , 2001, Chemosphere.

[15]  Peter F. Nelson,et al.  NON-METHANE EXHAUST COMPOSITION IN THE SYDNEY HARBOUR TUNNEL: A FOCUS ON BENZENE AND 1,3-BUTADIENE , 1996 .

[16]  W. J. Koehl,et al.  Effects of Gasoline Composition on Vehicle Engine-Out and Tailpipe Hydrocarbon Emissions - The Auto/Oil Air Quality Improvement Research Program , 1992 .

[17]  T. Elbir,et al.  Characterization of Volatile Organic Compounds (VOCs) and Their Sources in the Air of Izmir, Turkey , 2007, Environmental monitoring and assessment.

[18]  R. Harley,et al.  Effects of reformulated gasoline and motor vehicle fleet turnover on emissions and ambient concentrations of benzene. , 2006, Environmental science & technology.

[19]  J. A. de Gouw,et al.  Effects of mixing on evolution of hydrocarbon ratios in the troposphere , 2005 .

[20]  S. Kent Hoekman,et al.  Speciated Measurements and Calculated Reactivities of Vehicle Exhaust Emissions from Conventional and Reformulated Gasolines , 1992 .

[21]  Stefan Hausberger,et al.  Road vehicle emission factors development: A review , 2013 .

[22]  Douglas R Lawson,et al.  Assessment of Nontailpipe Hydrocarbon Emissions from Motor Vehicles. , 1999, Journal of the Air & Waste Management Association.

[23]  G. Bishop,et al.  Emissions reductions as a result of automobile improvement. , 2003, Environmental science & technology.

[24]  H. Guo,et al.  Characterization of hydrocarbons, halocarbons and carbonyls in the atmosphere of Hong Kong. , 2004, Chemosphere.