Long-Term Efficiency of Catalytic Converters Operating in Mexico City

Díaz, Luis A.; Schifter, I.; Rodríguez, R.; Avalos, Sergio; López, Gabriel; López-Salinas, E.

doi:10.1080/10473289.2001.10464308

Cited by 7 publications

(5 citation statements)

References 3 publications

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“…This is to be expected from vehicles with average mileage that often exceeded 1 million km. This is similar to evidence collected elsewhere (Díaz et al, 2001) and suggests that retrofitting programmes on captive fleets of spark ignition vehicles should be carefully considered first on pilot samples and, depending on results, consider extending them to a fleet level.…”

Section: Impact Of Emission Control Replacement On Emission Levelssupporting

confidence: 78%

Emission Factors for a Taxi Fleet Operating on Liquefied Petroleum Gas (LPG) as a Function of Speed and Road Slope

et al. 2018

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Real-driving emissions of NO x , CO, and THC, as well as fuel consumption (FC) were studied from 18 liquefied petroleum gas (LPG) fueled taxis operating in a metropolitan road network. Euro 2 to Euro 5 technology vehicles were measured with the use of portable emission measurement systems (PEMS). Statistical processing was implemented to derive mean emission levels for the different technologies. The taxis were measured from 6 months to 2.5 years after their catalysts and lambda sensors were replaced. The emission levels of Euro 4 taxis after catalyst replacement appear higher compared to pre-replacement levels, while pre-Euro 4 taxis emission levels were moderately reduced by the catalyst replacement. Overall, Euro 5 LPG taxis exhibit the lowest emissions, even below the respective regulated limits. The NH 3 and N 2 O pollutant levels of a Euro 5 LPG taxi measured in the lab were found at about half its NO x emissions. Different integration methods of PEMS data were investigated toward the development of emission factors, including both time-based and distance-based approaches at different resolutions. Distance-based integration in sections of 500 m was considered suitable, as this provides a large dataset for statistical confidence and sufficient resolution for link-based modeling. Based on this, FC and emission factors of NO x , CO, and THC as a function of speed and road slope are presented, separately for vehicles considered as normal and high emitters. Volatile organic compounds speciation of Euro 5 taxis showed that methane and butane are the most abundant hydrocarbon species in the exhaust.

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Section: Impact Of Emission Control Replacement On Emission Levelssupporting

confidence: 78%

Emission Factors for a Taxi Fleet Operating on Liquefied Petroleum Gas (LPG) as a Function of Speed and Road Slope

et al. 2018

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“…Three way catalysts (TWC) and computerized engine control (closed loop control using an oxygen sensor to regulate fuel injection) have been mandatory on new cars in Mexico since 1993. In 2001, an estimated 1.3 million vehicles (46%) were equipped with an exhaust catalyst, with 0.6 million catalysts being more than 6 years old (17).…”

Section: Introductionmentioning

confidence: 99%

Platinum Group Elements in Airborne Particles in Mexico City

Rauch

Peucker‐Ehrenbrink

Molina

et al. 2006

Environ. Sci. Technol.

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Automobile exhaust catalysts using platinum group elements (PGE) have been mandatory on new cars in the Mexico City Metropolitan Area (MCMA) since 1991. Platinum, Pd, Rh, Ir, and Os concentrations and the isotopic composition of Os were determined in PM10 samples from the MCMA. Samples were prepared by isotope dilution NiS fire assay, and analysis was performed by magnetic sector ICP-MS using a single collector instrument for Pt, Pd, Rh, and Ir analysis and a multicollector instrument for Os analysis. Pt, Pd, and Rh concentrations at a downtown location (Merced) increased from < or =1.7 pg of Pt m(-3), 2.7 (4.0) pg of Pd m(-3), and 1.2+/-0.9 pg of Rh m(-3) in 1991 to 9.6 +/- 1.8 pg of Pt m(-3), 10.2+/-1.8 pg of Pd m(-3), and 2.8 +/-0.6 pg of Rh m(-3) in 2003. Concentrations at five sites in MCMA in 2003 averaged 9.3+/-1.9 pg of Pt m(-3), 11+/-4 pg of Pd m(-3), and 3.2+/- 1.0 pg of Rh m(-3). In contrast, Ir and Os concentrations and Os isotopic composition remained relatively constant and were 0.08+/-0.04 pg of Ir m(-3), 0.030 +/-0.007 pg of Os m(-3), and 0.60+/-0.04, respectively, in the MCMA in 2003. Elevated Pt, Pd, and Rh concentrations in the MCMA are attributed to automobile catalysts. A Pt-Pd-Rh concentration peak in 1993 suggests that early catalysts emitted a larger amount of PGE, possibly due to factors inherent in the technology or the use of inappropriate gasoline. Therefore, this study suggests that the current introduction of automobile catalysts in developing countries may result in elevated PGE concentrations if it is not accompanied by infrastructures and policy measures supporting their efficient use.

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“…It is well known that emission of cars can increase dramatically, if the catalytic converter is not working properly (see e.g. in 2 ). Moreover, the regular checking of catalytic converters take place only in relatively long time intervals.…”

Section: Introductionmentioning

confidence: 99%