New insights to the use of ethanol in automotive fuels: A stable isotopic tracer for fossil- and bio-fuel combustion inputs to the atmosphere

Brian M. Giebel, Peter K. Swart, Daniel D. Riemer

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Ethanol is currently receiving increased attention because of its use as a biofuel or fuel additive and because of its influence on air quality. We used stable isotopic ratio measurements of 13C/ 12C in ethanol emitted from vehicles and a small group of tropical plants to establish ethanol's δ 13C end-member signatures. Ethanol emitted in exhaust is distinctly different from that emitted by tropical plants and can serve as a unique stable isotopic tracer for transportation-related inputs to the atmosphere. Ethanol's unique isotopic signature in fuel is related to corn, a C4 plant and the primary source of ethanol in the U.S. We estimated a kinetic isotope effect (KIE) for ethanol's oxidative loss in the atmosphere and used previous assumptions with respect to the fractionation that may occur during wet and dry deposition. A small number of interpretive model calculations were used for source apportionment of ethanol and to understand the associated effects resulting from atmospheric removal. The models incorporated our end-member signatures and ambient measurements of ethanol, known or estimated source strengths and removal magnitudes, and estimated KIEs associated with atmospheric removal processes for ethanol. We compared transportation-related ethanol signatures to those from biogenic sources and used a set of ambient measurements to apportion each source contribution in Miami, Florida-a moderately polluted, but well ventilated urban location.

Original languageEnglish (US)
Pages (from-to)6661-6669
Number of pages9
JournalEnvironmental Science and Technology
Volume45
Issue number15
DOIs
StatePublished - Aug 1 2011

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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