The global atmospheric budget of ethanol revisited

Kirstine, Wayne; Galbally, Ian E.

doi:10.5194/acp-12-545-2012

Cited by 48 publications

(35 citation statements)

References 61 publications

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“…Despite the large impact on human health and atmospheric chemistry dynamics, many uncertainties are found in terms of gas and particulate matter emissions from vehicles and their atmospheric reactivity, e.g. secondary organic aerosol formation (de Abrantes et al, 2009;Ferreira da Silva et al, 2010;Kirstine and Galbally, 2012).…”

Section: Introductionmentioning

confidence: 99%

Physical–chemical characterisation of the particulate matter inside two road tunnels in the São Paulo Metropolitan Area

Brito¹,

Rizzo²,

Herckès

et al. 2013

Atmos. Chem. Phys.

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Abstract. The notable increase in biofuel usage by the road transportation sector in Brazil during recent years has significantly altered the vehicular fuel composition. Consequently, many uncertainties are currently found in particulate matter vehicular emission profiles. In an effort to better characterise the emitted particulate matter, measurements of aerosol physical and chemical properties were undertaken inside two tunnels located in the São Paulo Metropolitan Area (SPMA). The tunnels show very distinct fleet profiles: in the Jânio Quadros (JQ) tunnel, the vast majority of the circulating fleet are light duty vehicles (LDVs), fuelled on average with the same amount of ethanol as gasoline. In the Rodoanel (RA) tunnel, the particulate emission is dominated by heavy duty vehicles (HDVs) fuelled with diesel (5 % biodiesel). In the JQ tunnel, PM 2.5 concentration was on average 52 µg m −3 , with the largest contribution of organic mass (OM, 42 %), followed by elemental carbon (EC, 17 %) and crustal elements (13 %). Sulphate accounted for 7 % of PM 2.5 and the sum of other trace elements was 10 %. In the RA tunnel, PM 2.5 was on average 233 µg m −3 , mostly composed of EC (52 %) and OM (39 %). Sulphate, crustal and the trace elements showed a minor contribution with 5 %, 1 %, and 1 %, respectively. The average OC : EC ratio in the JQ tunnel was 1.59 ± 0.09, indicating an important contribution of EC despite the high ethanol fraction in the fuel composition. In the RA tunnel, the OC : EC ratio was 0.49 ± 0.12, consistent with previous measurements of diesel-fuelled HDVs. Besides bulk carbonaceous aerosol measurement, polycyclic aromatic hydrocarbons (PAHs) were quantified. The sum of the PAHs concentration was 56 ± 5 ng m −3 and 45 ± 9 ng m −3 in the RA and JQ tunnel, respectively. In the JQ tunnel, benzo(a)pyrene (BaP) ranged from 0.9 to 6.7 ng m −3 (0.02-0. 1 ‰ of PM 2.5 ) whereas in the RA tunnel BaP ranged from 0.9 to 4.9 ng m −3 (0.004-0. 02 ‰ of PM 2.5 ), indicating an important relative contribution of LDVs emission to atmospheric BaP.Real-time measurements performed in both tunnels provided aerosol size distributions and optical properties. The average particle count yielded 73 000 cm −3 in the JQ tunnel and 366 000 cm −3 in the RA tunnel, with an average diameter of 48 nm in the former and 39 nm in the latter. Aerosol single scattering albedo, calculated from scattering and absorption observations in the JQ tunnel, indicates a value of 0.5 associated with LDVs. Such single scattering albedo is 20-50 % higher than observed in previous tunnel studies, possibly as a result of the large biofuel usage. Given the exceedingly high equivalent black carbon loadings in the RA tunnel, real time light absorption measurements were possible only in the JQ tunnel. Nevertheless, using EC measured from the filters, a single scattering albedo of 0.31 for the RA tunnel has been estimated. The results presented here characterise particulate matter emitted from nearly 1 million vehicles fuelled with a considerable amount of...

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Section: Introductionmentioning

confidence: 99%

Physical–chemical characterisation of the particulate matter inside two road tunnels in the São Paulo Metropolitan Area

Brito¹,

Rizzo²,

Herckès

et al. 2013

Atmos. Chem. Phys.

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“…The average total flux accounts for removal of between 6 and 17% of the atmospheric global ethanol depending on the source magnitude estimate [ Singh , ; Naik et al , ; Kirstine and Galbally , ; Millet et al , ]. This average flux is in the range of models based upon equilibrium with Henry's law, which predict a range from 1.4 to 5 Tg/yr [ Naik et al , , Kirstine and Galbally , , ]. The agreement of measured precipitation values with equilibrium gas solubility calculations suggests that ethanol concentrations in wet deposition are close to equilibrium with atmospheric concentrations.…”

Section: Resultsmentioning

confidence: 99%

“…Several studies have suggested that there is also a marine source, perhaps associated with upwelling [ Beale et al , ]; however, this has not yet been confirmed or quantified. The predicted significance of wetlands in producing ethanol is also generally unknown with estimates suggesting wetland ethanol production and internal cycling to be 100 to 200 Tg/yr [ Kirstine and Galbally , , ]. As with ethanol sources, estimates for the magnitude of sinks also vary tremendously from 15 to 70 Tg/yr [ Singh , ; Naik et al , ; Kirstine and Galbally , ; Millet et al , ].…”

Section: Introductionmentioning

confidence: 99%

“…The predicted significance of wetlands in producing ethanol is also generally unknown with estimates suggesting wetland ethanol production and internal cycling to be 100 to 200 Tg/yr [ Kirstine and Galbally , , ]. As with ethanol sources, estimates for the magnitude of sinks also vary tremendously from 15 to 70 Tg/yr [ Singh , ; Naik et al , ; Kirstine and Galbally , ; Millet et al , ]. The primary sink for ethanol from the atmosphere is reaction with hydroxyl radical with wet and dry deposition also playing a potentially significant role in removing the alcohol from the troposphere.…”

Section: Introductionmentioning

confidence: 99%

“…Despite the documented effects of ethanol emissions on atmospheric chemistry, global ethanol budget models have large uncertainties in the magnitude of the ethanol source, which varies from 15 to 42 Tg/yr [Singh, 2004;Naik et al, 2010;Kirstine and Galbally, 2012b;Millet et al, 2012]. Terrestrial vegetation is the largest source of ethanol to the atmosphere, followed by emissions from vehicles using ethanol as fuel; however, there is a considerable degree of uncertainty in these numbers.…”

Section: Introductionmentioning

confidence: 99%

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Removal of atmospheric ethanol by wet deposition

Felix

Willey

Thomas

et al. 2017

Global Biogeochemical Cycles

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The global wet deposition flux of ethanol is estimated to be 2.4 ± 1.6 Tg/yr with a conservative range of 0.2–4.6 Tg/yr based upon analyses of 219 wet deposition samples collected at 12 locations globally. This estimate calculated by using observed wet deposition ethanol concentrations is in agreement with previous models (1.4–5 Tg/yr) predicting the wet deposition sink using Henry's law coefficients and atmospheric ethanol concentrations. Wet deposition is estimated to remove between 6 and 17% of the total ethanol emitted to the atmosphere on an annual basis. The concentration of ethanol in marine rain (25 ± 6 nM) is an order of magnitude less than in the majority of terrestrial rains (345 ± 280 nM). Terrestrial rain samples collected in locations impacted by high local sources of biofuel usage and locations downwind from ethanol distilleries were an order of magnitude higher in ethanol concentration (3090 ± 448 nM) compared to rain collected in terrestrial locations not impacted by these sources. These results indicate that wet deposition of ethanol is heavily influenced by local sources. Results of this study are important because they suggest that as biofuel production and usage increase, the concentration of ethanol in the atmosphere will increase as well the wet deposition flux. Additional research constraining the sources, sinks, and atmospheric impacts of ethanol is necessary to better assist in the debate as whether or not to increase consumption of the alcohol as a biofuel.

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Low‐lying Negative Ion States Probed in Potassium – Ethanol Collisions

Lozano,

Kumar,

Pereira

et al. 2024

ChemPhysChem

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Dissociative electron transfer in collisions between neutral potassium atoms and neutral ethanol molecules yields mainly OH−, followed by C2H5O−, O−, CH3− and CH2−.The dynamics of negative ions have been investigated by recording time‐of‐flight mass spectra in a wide range of collision energies from 17.5 to 350 eV in the lab frame, where the branching ratios show a relevant energy dependence for low/intermediate collision energies.The dominant fragmentation channel in the whole energy range investigated has been assigned to the hydroxyl anion in contrast to oxygen anion from dissociative electron attachment (DEA) experiments. This result shows the relevant role of the electron donor in the vicinity of the temporary negative ion formed allowing access to reactions which are not thermodynamically attained in DEA experiments.The electronic state spectroscopy of such negative ions, was obtained from potassium cation energy loss spectra in the forward scattering direction at 205 eV impact energy, showing a prevalent Feshbach resonance at 9.36 ± 0.10 eV with character, while a less pronounced contribution assigned to a shape resonance has been obtained at 3.16 ± 0.10 eV.Quantum chemical calculations for the lowest‐lying unoccupied molecular orbitals in the presence of a potassium atom have been performed to support the experimental findings.

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The global atmospheric budget of ethanol revisited

Cited by 48 publications

References 61 publications

Physical–chemical characterisation of the particulate matter inside two road tunnels in the São Paulo Metropolitan Area

Physical–chemical characterisation of the particulate matter inside two road tunnels in the São Paulo Metropolitan Area

Removal of atmospheric ethanol by wet deposition

Low‐lying Negative Ion States Probed in Potassium – Ethanol Collisions

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