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| Titel |
Temporal variations in rainwater methanol |
| VerfasserIn |
J. D. Felix, S. B. Jones, G. B. Avery, J. D. Willey, R. N. Mead, R. J. Kieber |
| 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 ; 14, no. 19 ; Nr. 14, no. 19 (2014-10-07), S.10509-10516 |
| Datensatznummer |
250119080
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| Publikation (Nr.) |
 copernicus.org/acp-14-10509-2014.pdf |
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| Zusammenfassung |
| This work reports the first comprehensive analysis of methanol concentrations
in rainwater. Methanol concentrations measured in 49 rain events collected
between 28 August 2007 and 10 July 2008 in Wilmington, NC, USA, ranged from
below the detection limit of 6 nM to 9.3 μM with a volume-weighted
average concentration of 1 ± 0.2 μM. Methanol concentrations
in rainwater were up to ~200 times greater than concentrations
reported previously in marine waters, indicating wet deposition as a
potentially significant source of methanol to marine waters. Assuming that
these methanol concentrations are an appropriate proxy for global methanol
rainwater concentrations, the global methanol wet deposition sink is
estimated as 20 Tg yr−1, which implies that previous methanol budgets
underestimate removal by precipitation. Methanol concentrations in rainwater
did not correlate significantly with H+, NO3−, and NSS, which
suggests that the dominant source of the alcohol to rainwater is not
anthropogenic. However, methanol concentrations were strongly correlated with
acetaldehyde, which has a primarily biogenic input. The methanol
volume-weighted concentration during the summer
(2.7 ± 0.9 μM) was ~3 times that of the winter
(0.9 ± 0.2 μM), further promoting biogenic emissions as the
primary cause of temporal variations of methanol concentrations. Methanol
concentrations peaked in rainwater collected during the time period
12 p.m.–6 p.m. Peaking during this period of optimal sunlight implies a
possible relationship with photochemical methanol production, but there are
also increases in biogenic activity during this time period. Rain events with
terrestrial origin had greater concentrations than those of marine origin,
demonstrating the significance of the continental source of methanol in
rainwater. |
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