Real-World Vehicle Emissions: A Summary of the Sixteenth Coordinating Research Council On-Road Vehicle Emissions Workshop

Cadle, Steven H.; Ayala, Alberto; Black, Kevin; Fulper, Carl; Graze, R. Rob; Minassian, Fred; Murray, Hannah B.; Natarajan, Mani; Tennant, Christopher J.; Lawson, Douglas R.

doi:10.1080/10473289.2007.10465310

Cited by 11 publications

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“…An analysis of the data inputs used for estimating the PM2.5 emissions from mobile sources in the 2005 MNEI indicates that the average vehicle speed and temperature had the highest sensitivity on the MOVES2010a PM2.5 emission factors estimates. In general, PM2.5 emission factors were higher for higher average vehicle speeds, consistent with studies indicating higher PM emission rates observed under high engine load conditions (i.e., vehicle Table 1. speeds) (Kean et al, 2003;Cadle et al, 2007;Zavala et al, 2009b). Similarly, recent studies are consistent with the observation that fine PM emissions increase with engine load for diesel-powered engines and that volatile fraction of fine PM decreases with increasing load (Ziemmann et al, 2002;Kwon et al, 2003).…”

Section: Pm25 Emissionssupporting

confidence: 69%

Analysis of model-based PM2.5 emission factors for on-road mobile sources in Mexico

Zavala¹,

Barrera²,

Morante³

et al. 2013

Atmósfera

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RESUMENSe investigan los resultados del empleo del modelo US-EPA MOVES2010a para calcular los factores de emisión del parque vehicular mexicano, y se comparan dichos resultados con las estimaciones del Inventario Nacional de Emisiones de México (INEM) de 2005. El estudio muestra que los factores de emisión PM2.5 basados en modelos, actualizados a partir de estudios recientes, pueden tener un impacto significativo en la estimación de emisiones de PM2.5 procedentes de fuentes móviles en México. Porcentajes mayores de vehículos antiguos tienden a incrementar las estimaciones de emisiones PM2.5 cuando se utiliza el modelo MOVES2010a en comparación con las del INEM 2005; sin embargo, el impacto global sobre las emisiones de material particulado varía según la cantidad y antigüedad de los vehículos, y de acuerdo con los porcentajes de vehículos antiguos impulsados por diesel y gasolina en el parque vehicular de cada entidad federativa. Los resultados también indican que las estimaciones de PM2.5 con MOVES2010a fueron particularmente sensibles a la velocidad vehicular, la temperatura ambiente y el contenido de azufre, pero no a la humedad relativa. Hay una gran necesidad de comprender las características del material particulado fino emitido por vehículos impulsados por diesel o gasolina en las principales zonas urbanas de México. ABSTRACTThis study investigates the effects of using the US-EPA MOVES2010a model for estimating PM2.5 emission factors in the Mexican vehicle fleet; the results are compared with the current PM2.5 emissions estimates in the 2005 Mexican National Emissions Inventory (MNEI). Our results show that model-based PM2.5 emissions factors updated from recent studies can have significant impacts on the estimated PM2.5 emissions from mobile sources in Mexico. Higher fractions of older vehicles tend to increase PM2.5 emissions estimates using MOVES2010a with respect to the 2005 MNEI estimates; however, the overall impact on PM emissions varies depending on the vehicle population and vehicle age composition for each Mexican state fleet. These effects are primarily driven by the higher PM2.5 emission factors from the gasoline-powered vehicles and by the high fractions of older gasoline and diesel vehicles. The results also indicate that the estimated MOVES2010a PM2.5 emission factors for Mexico were particularly sensitive to vehicle speed, ambient temperature and sulfur content, but not the relative humidity. There is a strong need to better understand the characteristics of fine particulate matter (PM) emitted from gasoline and diesel-powered vehicles in major urban areas in Mexico.Keywords: PM2.5 emission factors, mobile sources, emissions inventory.Atmósfera 26(1), 109-124 (2013) 110 M. Zavala et al. IntroductionThe effects of atmospheric particulate matter (PM) on human health have been well documented in recent years; the overall literature provides reasonably compelling evidence that ambient PM air pollution contributes to cardiopulmonary morbidity and mortality (e.g., Pope, 2010). There is also e...

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Section: Pm25 Emissionssupporting

confidence: 69%

Analysis of model-based PM2.5 emission factors for on-road mobile sources in Mexico

Zavala¹,

Barrera²,

Morante³

et al. 2013

Atmósfera

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“…Other factors, including fuel composition, ambient conditions, driving modes and maintenance practices, also affect the variability of on-road mobile emissions within and across vehicles types (e.g., Cadle et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of mobile emissions contributions to Mexico City's emissions inventory using on-road and cross-road emission measurements and ambient data

Zavala¹,

Herndon²,

Wood³

et al. 2009

Preprint

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Abstract. Mobile emissions represent a significant fraction of the total anthropogenic emissions burden in the Mexico City Metropolitan Area (MCMA) and, therefore, it is crucial to use top-down techniques informed by on-road exhaust measurements to evaluate and improve traditional bottom-up official emissions inventory (EI) for the city. We present the measurements of on-road fleet-average emission factors obtained using the Aerodyne mobile laboratory in the MCMA in March 2006 as part of the MILAGRO/MCMA-2006 field campaign. A comparison of our on-road emission measurements with those obtained in 2003 using essentially the same measurement techniques and analysis methods indicates that, in the three year span, NO emission factors remain within the measured variability ranges whereas emission factors of aldehydes and aromatics species were reduced for all sampled driving conditions. We use a top-down fuel-based approach to evaluate the mobile emissions from the gasoline fleet estimated in the bottom-up official 2006 MCMA mobile sources. Within the range of measurement uncertainties, we found probable slight overpredictions of mean EI estimates on the order of 20–28% for CO and 14–20% for NO. However, we identify a probable EI underprediction of VOC mobile emissions between 1.4 and 1.9; although estimated benzene and toluene mobile emissions in the inventory seem to be well within the uncertainties of the corresponding emissions estimates. Aldehydes mobile emissions in the inventory, however, seem to be under predicted by factors of 3 for HCHO and 2 for CH3CHO. Our on-road measurement based estimate of annual emissions of organic mass from PM1 particles suggests a severe underprediction (larger than a factor of 4) of PM2.5 mobile emissions in the inventory. Analyses of ambient CO, NOx and CO/NOx concentration trends in the MCMA indicate that the early morning ambient CO/NOx ratio has decreased at a rate of about 1.9 ppm/ppm/year over the last two decades and that the decrease has been driven by reductions in CO levels rather than by NOx concentration changes, suggesting that the relative contribution of diesel vehicles to overall NOx levels has increased over time in the city. Despite the impressive increases in the size of the vehicle fleet between 2000 and 2006, the early morning ambient concentrations of CO and NOx have not increased accordingly, probably due to the reported low removal rates of older vehicles, which do not have emissions control technologies, and partially due to the much lower emissions from newer gasoline vehicles. This indicates that an emission-based air quality control strategy targeting large reductions of emissions from mobile sources should be directed towards a significant increase of the removal rate of older, highly-polluting, vehicles.

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“…On-road vehicle emission measurements have also revealed a strong dependence on vehicle speed and engine load (Pierson et al, 1996;Kean et al, 2003;Jazcilevich et al, 2007). Other factors, including fuel composition, ambient conditions, driving modes and maintenance practices, also affect the variability of on-road mobile emissions within and across vehicles types (e.g., Cadle et al, 2007).…”

mentioning

confidence: 99%

Evaluation of mobile emissions contributions to Mexico City's emissions inventory using on-road and cross-road emission measurements and ambient data

et al. 2009

View full text Add to dashboard Cite

Abstract. Mobile emissions represent a significant fraction of the total anthropogenic emissions burden in the Mexico City Metropolitan Area (MCMA) and, therefore, it is crucial to use top-down techniques informed by on-road exhaust measurements to evaluate and improve traditional bottom-up official emissions inventory (EI) for the city. We present the measurements of on-road fleet-average emission factors obtained using the Aerodyne mobile laboratory in the MCMA in March 2006 as part of the MILAGRO/MCMA-2006 field campaign. A comparison of our on-road emission measurements with those obtained in 2003 using essentially the same measurement techniques and analysis methods indicates that, in the three year span, NO emission factors remain within the measured variability ranges whereas emission factors of aldehydes and aromatics species were reduced for all sampled driving conditions.We use a top-down fuel-based approach to evaluate the mobile emissions from the gasoline fleet estimated in the bottom-up official 2006 MCMA mobile sources. Within the range of measurement uncertainties, we found probable slight overpredictions of mean EI estimates on the order of 20-28% for CO and 14-20% for NO. However, we identify a probable EI discrepancy of VOC mobile emissions between 1.4 and 1.9; although estimated benzene and toluene mobile emissions in the inventory seem to be well within the uncertainties of the corresponding emissions estimates. Aldehydes mobile emissions in the inventory, however, seem to be unCorrespondence to: M. Zavala (miguelz@mce2.org) derpredicted by factors of 3 for HCHO and 2 for CH 3 CHO. Our on-road measurement-based estimate of annual emissions of organic mass from PM 1 particles suggests a severe underprediction (larger than a factor of 4) of PM 2.5 mobile emissions in the inventory.Analyses of ambient CO, NO x and CO/NO x concentration trends in the MCMA indicate that the early morning ambient CO/NO x ratio has decreased at a rate of about 1.9 ppm/ppm/year over the last two decades due to reductions in CO levels rather than by NO x . These trends, together with the analysis of fuel sales and fleet size, suggest that the relative contribution of diesel vehicles to overall NO x levels has increased over time in the city. Despite the impressive increase in the size of the vehicle fleet between 2000 and 2006, the early morning ambient concentrations of CO and NO x have not increased accordingly, probably due to the reported low removal rates of older vehicles, which do not have emissions control technologies, and partially due to the much lower emissions from newer gasoline vehicles. This indicates that an emission-based air quality improvement strategy targeting large reductions of emissions from mobile sources should be directed towards a significant increase of the removal rate of older, highly-polluting, vehicles.

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Real-World Vehicle Emissions: A Summary of the Sixteenth Coordinating Research Council On-Road Vehicle Emissions Workshop

Cited by 11 publications

References 0 publications

Analysis of model-based PM2.5 emission factors for on-road mobile sources in Mexico

Analysis of model-based PM2.5 emission factors for on-road mobile sources in Mexico

Evaluation of mobile emissions contributions to Mexico City's emissions inventory using on-road and cross-road emission measurements and ambient data

Evaluation of mobile emissions contributions to Mexico City's emissions inventory using on-road and cross-road emission measurements and ambient data

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