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Title:
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Determination of anthropogenic and biogenic contribution to ambient volatile organic carbons
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Author(s):
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Published by:
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Publication date:
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ECN
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1-10-1998
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ECN report number:
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Document type:
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ECN-C--98-081
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ECN publication
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Number of pages:
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Full text:
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180
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Download PDF
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Abstract:
The ultimate goal of this project was to determine the ratio of biogenicand anthropogenic contribution to volatile organic emissions, based on the
"1"4C activity ("1"4C/"12C ratio) found in ambient air samples and to shed
light on the importance of anthropogenic contribution to VOC emissions. The
basic assumption behind the calculations was that the highest "1"4C content
can be found in purely biogenic material, the expected "1"4C level was that
of the presently measured background level in purely biogenic materials. In
order to achieve the ultimate goal of the project, several practical
challenges needed to be taken, including the development of two new sampling
methods for the collection of large-volume ambient air samples respectively
for hydrocarbon and for carbonyl analysis. Also, the participants needed to
improve the present state of art concerning analytical and sampling
techniques. The correctness of the experimental methods was proved with
laboratory intercomparison exercises and QA/QC samples. Sample preparation
for "1"4 C analysis has been established for the target compounds. Hence, the
present state of the art has progressed considerably in the field of
collecting, handling and preparing large volume air samples, and considerable
achievements have been made in the field of "1"4 C measurements to enable
acquisition of data from very small samples. The data acquired was thoroughly
and critically evaluated. A sizeable fraction of hydrocarbons as well as
total VOC was found to be of biogenic sources: the lowest contribution found
was 20% for hydrocarbons, but the overall biogenic contribution for total VOC
was found to be between 50 to 60% in hydrocarbons and carbonyls at sampling
location in Juelich (Germany), Aveiro (Portugal), as well as in Ispra and
Castelporziano (both in Italy). Some remaining recommendations include
collection and measurement of more samples to enable statistical evaluation
of the data. Based on the experience compiled and the technical improvements
achieved within the framework of this project, follow-up experiments can be
carried out with considerably less effort. 139 refs.
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