Compound-Specific Carbon Isotopic Composition of Ethanol in Brazil and US Vehicle Emissions and Wet Deposition
| Autor: | M. Lucia A.M. Campos, Rachel K. Thomas, Megumi S. Shimizu, J. David Felix, Ralph N. Mead, Chad S. Lane, G. Brooks Avery, Robert J. Kieber, Amanda Guy, Joan D. Willey, Matt Casas |
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| Rok vydání: | 2018 |
| Předmět: |
Carbon Isotopes
Ethanol 010504 meteorology & atmospheric sciences δ13C Atmosphere Stable isotope ratio chemistry.chemical_element General Chemistry Fractionation 010501 environmental sciences 01 natural sciences COMPOSIÇÃO QUÍMICA chemistry Isotopes of carbon Environmental chemistry Atmospheric chemistry Environmental Chemistry Environmental science Ethanol fuel Carbon Brazil Vehicle Emissions 0105 earth and related environmental sciences |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| ISSN: | 1520-5851 0013-936X |
| DOI: | 10.1021/acs.est.8b05325 |
| Popis: | Global atmospheric ethanol budget models include large uncertainties in the magnitude of ethanol emission sources and sinks. To apply stable isotope techniques to constrain ethanol emission sources, a headspace solid phase microextraction gas chromatograph-combustion-isotope ratio mass spectrometry method (HS-SPME-GC-C-IRMS) was developed to measure the carbon isotopic composition of aqueous phase ethanol at natural abundance levels (1-30 μM) with a precision of 0.4‰. The method was applied to determine the carbon isotope signatures (δ13C) of vehicle ethanol emission sources in Brazil (-12.8 ± 2.4‰) and the US (-9.8 ± 2.5‰), and to measure the carbon isotope composition of ethanol in wet deposition (-22.6 to -12.7‰). A two end-member isotope mixing model was developed using anthropogenic and biogenic end members and fractionation scenarios to estimate ethanol source contributions to wet deposition collected in Brazil and US. Mixing model results indicate anthropogenic sources contribute two and a half to four times more ethanol to the atmosphere than previously predicted in modeled global ethanol inventories. As established and developing countries continue to rapidly increase ethanol fuel consumption and subsequent emissions, understanding the magnitude of all ethanol sources and sinks will be essential for modeling future atmospheric chemistry and air quality impacts. |
| Databáze: | OpenAIRE |
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