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| Titel |
Observations of glyoxal and formaldehyde as metrics for the anthropogenic impact on rural photochemistry |
| VerfasserIn |
J. P. DiGangi, S. B. Henry, A. Kammrath, E. S. Boyle, L. Kaser, R. Schnitzhofer, M. Graus, A. Turnipseed, J.-H. Park, R. J. Weber, R. S. Hornbrook, C. A. Cantrell, R. L. Maudlin III, S. Kim, Y. Nakashima, G. M. Wolfe, Y. Kajii, E. C. Apel, A. H. Goldstein, A. Guenther, T. Karl, A. Hansel, F. N. Keutsch |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 20 ; Nr. 12, no. 20 (2012-10-22), S.9529-9543 |
| Datensatznummer |
250011521
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| Publikation (Nr.) |
 copernicus.org/acp-12-9529-2012.pdf |
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| Zusammenfassung |
| We present simultaneous fast, in-situ measurements of formaldehyde and
glyoxal from two rural campaigns, BEARPEX 2009 and BEACHON-ROCS, both located
in Pinus Ponderosa forests with emissions dominated by biogenic volatile
organic compounds (VOCs). Despite considerable variability in the
formaldehyde and glyoxal concentrations, the ratio of glyoxal to
formaldehyde, RGF, displayed a very regular diurnal cycle over
nearly 2 weeks of measurements. The only deviations in RGF were
toward higher values and were the result of a biomass burning event during
BEARPEX 2009 and very fresh anthropogenic influence during BEACHON-ROCS.
Other rapid changes in glyoxal and formaldehyde concentrations have hardly
any affect on RGF and could reflect transitions between low and
high NO regimes. The trend of increased RGF from both
anthropogenic reactive VOC mixtures and biomass burning compared to biogenic
reactive VOC mixtures is robust due to the short timescales over which the
observed changes in RGF occurred. Satellite retrievals, which
suggest higher RGF for biogenic areas, are in contrast to our
observed trends. It remains important to address this discrepancy, especially
in view of the importance of satellite retrievals and in situ measurements
for model comparison. In addition, we propose that RGF represents
a useful metric for biogenic or anthropogenic reactive VOC mixtures and, in
combination with absolute concentrations of glyoxal and formaldehyde,
furthermore represents a useful metric for the extent of anthropogenic
influence on overall reactive VOC processing via NOx. In
particular, RGF yields information about not simply the VOCs
dominating reactivity in an airmass, but the VOC processing itself that is
directly coupled to ozone and secondary organic aerosol production. |
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