An Evaluation of the LPG Vehicles Program in the Metropolitan Area of Mexico City

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

doi:10.1080/10473289.2000.10464010

Cited by 16 publications

(7 citation statements)

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“…Although LPG powered vehicles represent less than 1% of the total fleet, they should also be considered important sources. Schifter et al (2000) evaluated the LPG vehicles program implemented in Mexico City and found that 95% of them have emissions that exceed those required by environmental regulations. The LPG fleet is composed mainly by vehicles used intensively (light and heavy duty trucks, and small buses with a 20 passenger capacity).…”

Section: Comparison Of Ambient Voc Concentrations To Vehicles Exhaustmentioning

confidence: 99%

Distribution, magnitudes, reactivities, ratios and diurnal patterns of volatile organic compounds in the Valley of Mexico during the MCMA 2002 and 2003 field campaigns

Velasco¹,

Lamb²,

Westberg³

et al. 2006

Preprint

119

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Abstract. A wide array of volatile organic compound (VOC) measurements was conducted in the Valley of Mexico during the MCMA-2002 and 2003 field campaigns. Study sites included locations in the urban core, in a heavily industrial area and at boundary sites in rural landscapes. In addition, a novel mobile-laboratory-based conditional sampling method was used to collect samples dominated by fresh on-road vehicle exhaust to identify those VOCs whose ambient concentrations were primarily due to vehicle emissions. Five distinct analytical techniques were used: whole air canister samples with Gas Chromatography/Flame Ionization Detection (GC-FID), on-line chemical ionization using a Proton Transfer Reaction Mass Spectrometer (PTR-MS), continuous real-time detection of olefins using a Fast Olefin Sensor (FOS), and long path measurements using UV Differential Optical Absorption Spectrometers (DOAS). The simultaneous use of these techniques provided a wide range of individual VOC measurements with different spatial and temporal scales. The VOC data were analyzed to understand concentration and spatial distributions, diurnal patterns, origin and reactivity in the atmosphere of Mexico City. The VOC burden (in ppbC) was dominated by alkanes (60%), followed by aromatics (15%) and olefins (5%). The remaining 20% was a mix of alkynes, halogenated hydrocarbons, oxygenated species (esters, ethers, etc.) and other unidentified VOCs. However, in terms of ozone production, olefins were the most relevant hydrocarbons. Elevated levels of toxic hydrocarbons, such as 1,3-butadiene, benzene, toluene and xylenes were also observed. Results from these various analytical techniques showed that vehicle exhaust is the main source of VOCs in Mexico City and that diurnal patterns depend on vehicular traffic. Finally, examination of the VOC data in terms of lumped modeling VOC classes and its comparison to the VOC lumped emissions reported in other photochemical air quality modeling studies suggests that some, but not all, VOC classes are underestimated in the emissions inventory by factors of 1.1 to 3.

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Section: Comparison Of Ambient Voc Concentrations To Vehicles Exhaustmentioning

confidence: 99%

Distribution, magnitudes, reactivities, ratios and diurnal patterns of volatile organic compounds in the Valley of Mexico during the MCMA 2002 and 2003 field campaigns

Velasco¹,

Lamb²,

Westberg³

et al. 2006

Preprint

119

View full text Add to dashboard Cite

show abstract

“…Although LPG powered vehicles represent less than 1% of the total fleet, they are also important emission sources. The LPG fleet is composed mainly of vehicles used intensively (light and heavy duty trucks, and microbuses with 20-passenger capacity); 95% of them have emissions that exceed the standards required by local environmental regulations (Schifter et al, 2000). The LPG leaked from households at nighttime accumulates in the shallow unstable boundary layer and adds to the morning emissions from traffic and from LPG transmission systems.…”

Section: Vertical Distribution Of Vocsmentioning

confidence: 99%

Vertical distribution of ozone and VOCs in the low boundary layer of Mexico City

Velasco

Márquez²,

Bueno³

et al. 2008

Atmos. Chem. Phys.

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Abstract. The evolution of ozone (O3) and 13 volatile organic compounds (VOCs) in the boundary layer of Mexico City was investigated during 2000–2004 to improve our understanding of the complex interactions between those trace gases and meteorological variables, and their influence on the air quality of a polluted megacity. A tethered balloon, fitted with electrochemical and meteorological sondes, was used to obtain detailed vertical profiles of O3 and meteorological parameters up to 1000 m above ground during part of the diurnal cycle (02:00–18:00 h). VOCs samples were collected up to 200 m by pumping air to canisters with a Teflon tube attached to the tether line. Overall, features of these profiles were found to be consistent with the formation of an upper residual layer during nighttime carrying over a fraction of the O3 from the previous day that contributes to the background concentration in surrounding regions. At the same time the release of heat stored in the urban surface forms a shallow unstable layer close to the ground, where the nocturnal emissions are trapped. After sunrise an O3 balance is determined by photochemical production, entrainment from the upper residual layer and destruction by titration with nitric oxide, delaying the ground-level O3 rise by 2 h. The subsequent evolution of the conductive boundary layer and vertical distribution of pollutants are discussed in terms of the energy balance, the presence of turbulence and the atmospheric stability.

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“…1% of the total fleet, they are also important sources. The LPG fleet is composed mainly of vehicles used intensively (light and heavy duty trucks, and microbuses with 20-passenger capacity); 95% of them have emissions that exceed those required by local environmental regulations (Schifter et al, 2000). The LPG leaked at nighttime from households accumulates in the shallow unstable boundary layer and adds to the morning emissions from traffic and from LPG transmission systems.…”

Section: Egumentioning

confidence: 99%

Vertical distribution of ozone and VOCs in the low boundary layer of Mexico City

Velasco¹,

Márquez²,

Bueno³

et al. 2007

Preprint

View full text Add to dashboard Cite

Abstract. The evolution of ozone and 13 volatile organic compounds (VOCs) in the boundary layer of Mexico City was investigated during 2000–2004 to improve our understanding of the complex interactions between those trace gases and meteorological variables, and their influence on the air quality of a polluted megacity. A tethered balloon, fitted with electrochemical and meteorological sondes, was used to obtain detailed vertical profiles of ozone and meteorological parameters up to 1000 m above ground during part of the diurnal cycle (02:00–18:00 h). VOCs samples were collected up to 200 m by pumping air to canisters with a Teflon tube attached to the tether line. Overall, features of these profiles were found to be consistent with a simple picture of nighttime trapping of ozone in an upper residual layer and of VOCs in a shallow unstable layer above the ground. After sunrise an ozone balance is determined by photochemical production, entrainment from the upper residual layer and destruction by titration with NO, delaying the ground-level ozone rise by 2 h. The subsequent evolution of the conductive boundary layer and vertical distribution of pollutants are discussed in terms of the energy balance, the presence of turbulence and the atmospheric stability.

show abstract

An Evaluation of the LPG Vehicles Program in the Metropolitan Area of Mexico City

Cited by 16 publications

References 0 publications

Distribution, magnitudes, reactivities, ratios and diurnal patterns of volatile organic compounds in the Valley of Mexico during the MCMA 2002 and 2003 field campaigns

Distribution, magnitudes, reactivities, ratios and diurnal patterns of volatile organic compounds in the Valley of Mexico during the MCMA 2002 and 2003 field campaigns

Vertical distribution of ozone and VOCs in the low boundary layer of Mexico City

Vertical distribution of ozone and VOCs in the low boundary layer of Mexico City

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