Automobile exhaust as a source of 13C- and D-enriched atmospheric methane in urban areas

Nakagawa, Fumiko; Tsunogai, Urumu; Komatsu, Daisuke; Yamada, Keita; Yoshida, Naohiro; Moriizumi, Jun; Nagamine, Koichiro; Iida, Takao; Ikebe, Yukimasa

doi:10.1016/j.orggeochem.2005.01.003

Cited by 35 publications

(22 citation statements)

References 45 publications

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“…For vehicle exhaust, progress has recently been achieved through isotopic studies of e.g. carbon monoxide, CO (Tsunogai et al, 2003), methane, CH 4 (Chanton et al, 2000;Nakagawa et al, 2005), and nitrous oxide, N 2 O (Toyoda et al, 2008). Here we present results from a study on a passenger car engine for which we have measured pre-and post-catalytic H 2 concentrations and -to our knowledge for the first time -H/D signatures under variable engine and fuel settings.…”

Section: Introductionmentioning

confidence: 95%

“…1 and 4) are in close agreement with these findings. Recent field studies of anthropogenically polluted air in Europe and North America have shown H 2 /CO ratios to vary in a relatively narrow range of ∼0.3-0.6 (Novelli et al, 1999;Barnes et al, 2003;Steinbacher et al, 2007;Aalto et al, 2009), and when the traffic component was isolated from other H 2 and CO sources and sinks, yielded ratios of 0.48-0.51 Hammer et al, 2009). …”

Section: Exhaust Ratios Of H 2 /Co H 2 /Co 2 and Co/comentioning

confidence: 99%

“…Its source and sink strengths are given here as ranges found in the literature (Novelli et al, 1999;Hauglustaine and Ehhalt, 2002;Sanderson et al, 2003;Rhee et al, 2006;Price et al, 2007;5708 M. K. Vollmer et al: Molecular hydrogen from traffic sources are in-situ photochemical production from methane (CH 4 ) and other hydrocarbons (30-77 Tg a −1 ), fossil fuel emissions (11-20 Tg a −1 ), biomass burning (10 -20 Tg a −1 ), and minor emissions from microbial nitrogen (N 2 ) fixation on land and in the oceans (6-10 Tg a −1 ). The dominant sink of H 2 is enzymatic destruction in soil (55-88 Tg a −1 ), but there is also considerable removal through oxidation by the hydroxyl radical in the atmosphere (15-19 Tg a −1 ).…”

Section: Introductionmentioning

confidence: 99%

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Molecular hydrogen (H2) emissions and their isotopic signatures (H/D) from a motor vehicle: implications on atmospheric H2

et al. 2010

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Abstract. Molecular hydrogen (H 2 ), its isotopic signature (deuterium/hydrogen, δD), carbon monoxide (CO), and other compounds were studied in the exhaust of a passenger car engine fuelled with gasoline or methane and run under variable air-fuel ratios and operating modes. H 2 and CO concentrations were largely reduced downstream of the three-way catalytic converter (TWC) compared to levels upstream, and showed a strong dependence on the air-fuel ratio (expressed as lambda, λ). The isotopic composition of H 2 ranged from δD=−140‰ to δD = −195‰ upstream of the TWC but these values decreased to −270‰ to −370‰ after passing through the TWC. Post-TWC δD values for the fuelrich range showed a strong dependence on TWC temperature with more negative δD for lower temperatures. These effects are attributed to a rapid temperature-dependent H-D isotope equilibration between H 2 and water (H 2 O). In addition, post TWC δD in H 2 showed a strong dependence on the fraction of removed H 2 , suggesting isotopic enrichment during catalytic removal of H 2 with enrichment factors (ε) ranging from −39.8‰ to −15.5‰ depending on the operating mode. Our results imply that there may be considerable variability in real-world δD emissions from vehicle exhaust, which may mainly depend on TWC technology and exhaust temperature regime. This variability is suggestive of a δD from traffic that varies over time, by season, and by geographical location. An earlier-derived integrated pure (end-member) δD from anthropogenic activities of −270‰ (Rahn et al., 2002) Correspondence to: M. K. Vollmer (martin.vollmer@empa.ch) can be explained as a mixture of mainly vehicle emissions from cold starts and fully functional TWCs, but enhanced δD values by >50‰ are likely for regions where TWC technology is not fully implemented. Our results also suggest that a full hydrogen isotope analysis on fuel and exhaust gas may greatly aid at understanding process-level reactions in the exhaust gas, in particular in the TWC.

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Section: Introductionmentioning

confidence: 95%

Section: Exhaust Ratios Of H 2 /Co H 2 /Co 2 and Co/comentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Molecular hydrogen (H2) emissions and their isotopic signatures (H/D) from a motor vehicle: implications on atmospheric H2

et al. 2010

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“…The majority of anthropogenic carbon dioxide (CO 2 ) is released in the combustion of fossil fuels for heating, electricity and transport, the latter of which is particularly important in the urban environment. The major sources of methane (CH 4 ) in city environments are leakage from natural gas infrastructure, landfill sites, wastewater treatment and transport emissions (Lowry et al, 2001;Nakagawa et al, 2005;Townsend-Small et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Analysis of the potential of near-ground measurements of CO2 and CH4 in London, UK, for the monitoring of city-scale emissions using an atmospheric transport model

et al. 2016

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Abstract. Carbon dioxide (CO 2 ) and methane (CH 4 ) mole fractions were measured at four near-ground sites located in and around London during the summer of 2012 with a view to investigating the potential of assimilating such measurements in an atmospheric inversion system for the monitoring of the CO 2 and CH 4 emissions in the London area. These data were analysed and compared with simulations using a modelling framework suited to building an inversion system: a 2 km horizontal resolution south of England configuration of the transport model CHIMERE driven by European Centre for Medium-Range Weather Forecasts (ECMWF) meteorological forcing, coupled to a 1 km horizontal resolution emission inventory (the UK National Atmospheric Emission Inventory). First comparisons reveal that local sources, which cannot be represented in the model at a 2 km resolution, have a large impact on measurements. We evaluate methods to filter out the impact of some of the other critical sources of discrepancies between the measurements and the model simulation except that of the errors in the emission inventory, which we attempt to isolate. Such a separation of the impact of errors in the emission inventory should make it easier to identify the corrections that should be applied to the inventory. Analysis is supported by observations from meteorological sites around the city and a 3-week period of atmospheric mixing layer height estimations from lidar measurements. The difficulties of modelling the mixing layer depth and thus CO 2 and CH 4 concentrations during the night, morning and late afternoon lead to focusing on the afternoon period for all further analyses. The discrepancies between observations and model simulations are high for both CO 2 and CH 4 (i.e. their root mean square (RMS) is between 8 and 12 parts per million (ppm) for CO 2 and between 30 and 55 parts per billion (ppb) for CH 4 at a given site). By analysing the gradients between the urban sites and a suburban or rural reference site, we are able to decrease the impact of uncertainties in the fluxes and transport outside the London area and in the model domain boundary conditions. We are thus able to better focus attention on the signature of London urban CO 2 and CH 4 emissions in the atmospheric CO 2 and CH 4 concentrations. This considerably improves the statistical agreement between the model and observations for CO 2 (with modeldata RMS discrepancies that are between 3 and 7 ppm) and to a lesser degree for CH 4 (with model-data RMS discrepancies that are between 29 and 38 ppb). Between one of the urban sites and either the rural or suburban reference site, selecting the gradients during periods wherein the reference site is upwind of the urban site further decreases the statistics of the discrepancies in general, though not systematically. In a further attempt to focus on the signature of the city anthropogenic emission in the mole fraction measurements, we use a theoretical ratio of gradients of carbon monoxide (CO) to gradients of CO 2 from fossil fuel emiss...

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“…This value agrees very well with the measured isotope signature of natural gas being used in Krakow (−54.4±0.6‰) and points to leakages in the distribution network of this gas as the main anthropogenic source of CH 4 in the local atmosphere". Nakagawa (Nakagawa et al, 2005), using the stable carbon and hydrogen isotopic compositions (δ 13 C www.intechopen.com…”

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confidence: 99%

Variation of Greenhouse Gases in Urban Areas-Case Study: CO2, CO and CH4 in Three Romanian Cities

Haiduc¹,

Beldean‐Galea²

2011

Air Quality-Models and Applications

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Automobile exhaust as a source of 13C- and D-enriched atmospheric methane in urban areas

Cited by 35 publications

References 45 publications

Molecular hydrogen (H<sub>2</sub>) emissions and their isotopic signatures (H/D) from a motor vehicle: implications on atmospheric H<sub>2</sub>

Molecular hydrogen (H<sub>2</sub>) emissions and their isotopic signatures (H/D) from a motor vehicle: implications on atmospheric H<sub>2</sub>

Analysis of the potential of near-ground measurements of CO<sub>2</sub> and CH<sub>4</sub> in London, UK, for the monitoring of city-scale emissions using an atmospheric transport model

Variation of Greenhouse Gases in Urban Areas-Case Study: CO2, CO and CH4 in Three Romanian Cities

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Automobile exhaust as a source of 13C- and D-enriched atmospheric methane in urban areas

Cited by 35 publications

References 45 publications

Molecular hydrogen (H&lt;sub&gt;2&lt;/sub&gt;) emissions and their isotopic signatures (H/D) from a motor vehicle: implications on atmospheric H&lt;sub&gt;2&lt;/sub&gt;

Molecular hydrogen (H&lt;sub&gt;2&lt;/sub&gt;) emissions and their isotopic signatures (H/D) from a motor vehicle: implications on atmospheric H&lt;sub&gt;2&lt;/sub&gt;

Analysis of the potential of near-ground measurements of CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; in London, UK, for the monitoring of city-scale emissions using an atmospheric transport model

Variation of Greenhouse Gases in Urban Areas-Case Study: CO2, CO and CH4 in Three Romanian Cities

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Molecular hydrogen (H<sub>2</sub>) emissions and their isotopic signatures (H/D) from a motor vehicle: implications on atmospheric H<sub>2</sub>

Molecular hydrogen (H<sub>2</sub>) emissions and their isotopic signatures (H/D) from a motor vehicle: implications on atmospheric H<sub>2</sub>

Analysis of the potential of near-ground measurements of CO<sub>2</sub> and CH<sub>4</sub> in London, UK, for the monitoring of city-scale emissions using an atmospheric transport model