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| Titel |
Receptor modeling of near-roadway aerosol mass spectrometer data in Las Vegas, Nevada, with EPA PMF |
| VerfasserIn |
S. G. Brown, T. Lee, G. A. Norris, P. T. Roberts, J. L. Jr. Collett, P. Paatero, D. R. Worsnop |
| 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. 1 ; Nr. 12, no. 1 (2012-01-05), S.309-325 |
| Datensatznummer |
250010436
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| Publikation (Nr.) |
 copernicus.org/acp-12-309-2012.pdf |
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| Zusammenfassung |
| Ambient non-refractory PM1 aerosol particles were measured with an
Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-AMS)
at an elementary school 18 m from the US 95 freeway soundwall in Las
Vegas, Nevada, during January 2008. Additional collocated continuous
measurements of black carbon (BC), carbon monoxide (CO), nitrogen oxides
(NOx), and meteorological data were collected. The US~Environmental
Protection Agency's (EPA) positive matrix factorization (PMF) data analysis
tool was used to apportion organic matter (OM) as measured by HR-AMS, and
rotational tools in EPA PMF were used to better characterize the solution
space and pull resolved factors toward known source profiles. Three- to
six-factor solutions were resolved. The four-factor solution was the most
interpretable, with the typical AMS PMF factors of hydrocarbon-like organic
aerosol (HOA), low-volatility oxygenated organic aerosol (LV-OOA), biomass
burning organic aerosol (BBOA), and semi-volatile oxygenated organic aerosol
(SV-OOA). When the measurement site was downwind of the freeway, HOA
composed about half the OM, with SV-OOA and LV-OOA accounting for the rest.
Attempts to pull the PMF factor profiles toward source profiles were
successful but did not qualitatively change the results, indicating that
these factors are very stable. Oblique edges were present in G-space plots,
suggesting that the obtained rotation may not be the most plausible one.
Since solutions found by pulling the profiles or using Fpeak retained these
oblique edges, there appears to be little rotational freedom in the base
solution. On average, HOA made up 26% of the OM, while LV-OOA was highest
in the afternoon and accounted for 26% of the OM. BBOA occurred in the
evening hours, was predominantly from the residential area to the north, and
on average constituted 12% of the OM; SV-OOA accounted for the remaining
third of the OM. Use of the pulling techniques available in EPA PMF and ME-2
suggested that the four-factor solution was very stable. |
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