A Driving Cycle for Vehicle Emissions Estimation in the Metropolitan Area of Mexico City

Abstract. A mobile laboratory was used to measure on-road vehicle emission ratios during the MCMA-2003 field campaign held during the spring of 2003 in the Mexico City Metropolitan Area (MCMA). The measured emission ratios represent a sample of emissions of in-use vehicles under real world driving conditions for the MCMA. From the relative amounts of NOx and selected VOC's sampled, the results indicate that the technique is capable of differentiating among vehicle categories and fuel type in real world driving conditions. Emission ratios for NOx, NOy, NH3, H2CO, CH3CHO, and other selected volatile organic compounds (VOCs) are presented for chase sampled vehicles and fleet averaged emissions. Results indicate that colectivos, particularly CNG-powered colectivos, are potentially significant contributors of NOx and aldehydes in the MCMA. Similarly, ratios of selected VOCs and NOy showed a strong dependence on traffic mode. These results are compared with the vehicle emissions inventory for the MCMA, other vehicle emissions measurements in the MCMA, and measurements of on-road emissions in US cities. Our estimates for motor vehicle emissions of benzene, toluene, formaldehyde, and acetaldehyde in the MCMA indicate these species are present in concentrations higher than previously reported. The high motor vehicle aldehyde emissions may have an impact on the photochemistry of urban areas.

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04/01564 Impact of sulfur-in-gasoline on motor vehicle emissions in the metropolitan area of Mexico City

Fuel and Energy Abstracts ◽

10.1016/s0140-6701(04)90390-6 ◽

2004 ◽

Vol 45 (3) ◽

pp. 212

Keyword(s):

Mexico City ◽

Metropolitan Area ◽

Vehicle Emissions ◽

Motor Vehicle ◽

Motor Vehicle Emissions

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Characterization of on-road vehicle emissions in the Mexico City Metropolitan Area using a mobile laboratory in chase and fleet average measurement modes during the MCMA-2003 field campaign

Atmospheric Chemistry and Physics ◽

10.5194/acp-6-5129-2006 ◽

2006 ◽

Vol 6 (12) ◽

pp. 5129-5142 ◽

Cited By ~ 88

Author(s):

M. Zavala ◽

S. C. Herndon ◽

R. S. Slott ◽

E. J. Dunlea ◽

L. C. Marr ◽

...

Keyword(s):

Mexico City ◽

Metropolitan Area ◽

Real World ◽

Vehicle Emissions ◽

Motor Vehicle ◽

Nox Emissions ◽

Mobile Laboratory ◽

Field Campaign ◽

Emissions Inventory ◽

Emission Ratios

Abstract. A mobile laboratory was used to measure on-road vehicle emission ratios during the MCMA-2003 field campaign held during the spring of 2003 in the Mexico City Metropolitan Area (MCMA). The measured emission ratios represent a sample of emissions of in-use vehicles under real world driving conditions for the MCMA. From the relative amounts of NOx and selected VOC's sampled, the results indicate that the technique is capable of differentiating among vehicle categories and fuel type in real world driving conditions. Emission ratios for NOx, NOy, NH3, H2CO, CH3CHO, and other selected volatile organic compounds (VOCs) are presented for chase sampled vehicles in the form of frequency distributions as well as estimates for the fleet averaged emissions. Our measurements of emission ratios for both CNG and gasoline powered "colectivos" (public transportation buses that are intensively used in the MCMA) indicate that – in a mole per mole basis – have significantly larger NOx and aldehydes emissions ratios as compared to other sampled vehicles in the MCMA. Similarly, ratios of selected VOCs and NOy showed a strong dependence on traffic mode. These results are compared with the vehicle emissions inventory for the MCMA, other vehicle emissions measurements in the MCMA, and measurements of on-road emissions in U.S. cities. We estimate NOx emissions as 100 600±29 200 metric tons per year for light duty gasoline vehicles in the MCMA for 2003. According to these results, annual NOx emissions estimated in the emissions inventory for this category are within the range of our estimated NOx annual emissions. Our estimates for motor vehicle emissions of benzene, toluene, formaldehyde, and acetaldehyde in the MCMA indicate these species are present in concentrations higher than previously reported. The high motor vehicle aldehyde emissions may have an impact on the photochemistry of urban areas.

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A Health Risk Assessment of Lead and Other Metals in Pharmaceutical Herbal Products and Dietary Supplements Containing Ginkgo biloba in the Mexico City Metropolitan Area

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18168285 ◽

2021 ◽

Vol 18 (16) ◽

pp. 8285

Author(s):

Patricia Rojas ◽

Elizabeth Ruiz-Sánchez ◽

Camilo Ríos ◽

Ángel Ruiz-Chow ◽

Aldo A. Reséndiz-Albor

Keyword(s):

Health Risk ◽

Dietary Supplements ◽

Mexico City ◽

Metropolitan Area ◽

Ginkgo Biloba ◽

Graphite Furnace ◽

Human Health Risk ◽

Daily Intake ◽

Herbal Remedies ◽

Herbal Products

The use of the medicinal plant Ginkgo biloba has increased worldwide. However, G. biloba is capable of assimilating both essential and toxic metals, and the ingestion of contaminated products can cause damage to health. The aim of this study was to investigate the safety of manganese (Mn), copper (Cu), lead (Pb), arsenic (As), and cadmium (Cd) in 26 items containing Ginkgo biloba (pharmaceutical herbal products, dietary supplements, and traditional herbal remedies) purchased in the metropolitan area of Mexico City. Metal analysis was performed using a graphite furnace atomic absorption spectrometer. All of the products were contaminated with Pb, 54% of them with As, and 81% with Cd. The lowest values of Pb, As, and Cd were detected in pharmaceutical herbal products > dietary supplements > traditional herbal remedies. The daily intake dose (DID) of pharmaceutical herbal products was within the established limits for the five metals. Dietary supplements and traditional herbal remedies exceeded the DID limits for Pb. The hazard quotients estimation and non-carcinogenic cumulative hazard estimation index for Mn, As, and Cd indicated no human health risk. Our results suggest that products containing G. biloba for sale in Mexico are not a health risk.

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