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| Titel |
Temperature-dependent accumulation mode particle and cloud nuclei concentrations from biogenic sources during WACS 2010 |
| VerfasserIn |
L. Ahlm, K. M. Shakya, L. M. Russell, J. C. Schroder, J. P. S. Wong, S. J. Sjostedt, K. L. Hayden, J. Liggio, J. J. B. Wentzell, H. A. Wiebe, C. Mihele, W. R. Leaitch, A. M. Macdonald |
| 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 ; 13, no. 6 ; Nr. 13, no. 6 (2013-03-25), S.3393-3407 |
| Datensatznummer |
250018539
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| Publikation (Nr.) |
 copernicus.org/acp-13-3393-2013.pdf |
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| Zusammenfassung |
Submicron aerosol particles collected simultaneously at the mountain peak
(2182 m a.s.l.) and at a forested mid-mountain site (1300 m a.s.l.) on
Whistler Mountain, British Columbia, Canada, during June and July 2010 were
analyzed by Fourier transform infrared (FTIR) spectroscopy for
quantification of organic functional groups. Positive matrix factorization
(PMF) was applied to the FTIR spectra. Three PMF factors associated with (1)
combustion, (2) biogenics, and (3) vegetative detritus were identified at
both sites. The biogenic factor was correlated with both temperature and
several volatile organic compounds (VOCs). The combustion factor dominated
the submicron particle mass during the beginning of the campaign, when the
temperature was lower and advection was from the Vancouver area, but as the
temperature started to rise in early July, the biogenic factor came to
dominate as a result of increased emissions of biogenic VOCs, and thereby
increased formation of secondary organic aerosol (SOA). On average, the
biogenic factor represented 69% and 49% of the submicron organic
particle mass at Whistler Peak and at the mid-mountain site, respectively.
The lower fraction at the mid-mountain site was a result of more vegetative
detritus there, and also higher influence from local combustion sources.
The biogenic factor was strongly correlated (r~0.9) to number
concentration of particles with diameter (Dp)> 100 nm,
whereas the combustion factor was better correlated to number concentration
of particles with Dp<100 nm (r~0.4). The number
concentration of cloud condensation nuclei (CCN) was correlated
(r~0.7) to the biogenic factor for supersaturations (S) of
0.2% or higher, which indicates that particle condensational growth from
biogenic vapors was an important factor in controlling the CCN concentration
for clouds where S≥0.2%. Both the number concentration of particles
with Dp>100 nm and numbers of CCN for S≥0.2% were
correlated to temperature. Considering the biogenic influence, these results
indicate that temperature was a primary factor controlling these CCN
concentrations at 0.2% supersaturation. |
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