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| Titel |
Intra-community spatial variability of particulate matter size distributions in Southern California/Los Angeles |
| VerfasserIn |
M. Krudysz, K. Moore, M. Geller, C. Sioutas, J. Froines |
| 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 ; 9, no. 3 ; Nr. 9, no. 3 (2009-02-12), S.1061-1075 |
| Datensatznummer |
250006829
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| Publikation (Nr.) |
 copernicus.org/acp-9-1061-2009.pdf |
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| Zusammenfassung |
| Ultrafine particle (UFP) number concentrations vary significantly on small
spatial and temporal scales due to their short atmospheric lifetimes and
multiplicity of sources. To determine UFP exposure gradients within a
community, simultaneous particle number concentration measurements at a
network of sites are necessary. Concurrent particle number size distribution
measurements aid in identifying UFP sources, while providing data to
investigate local scale effects of both photochemical and physical processes
on UFP. From April to December 2007, we monitored particle number size
distributions at 13 sites within 350 m–11 km of each other in the vicinity
of the Ports of Los Angeles and Long Beach using Scanning Mobility Particle
Sizers (SMPS). Typically, three SMPS units were simultaneously deployed and
rotated among sites at 1–2 week intervals. Total particle number
concentration measurements were conducted continuously at all sites.
Seasonal and diurnal number size distribution patterns are complex, highly
dependent on local meteorology, nearby PM sources, and times of day, and
cannot be generalized over the study area nor inferred from one or two
sampling locations. Spatial variation in particle number size distributions
was assessed by calculating the coefficient of divergence (COD) and
correlation coefficients (r) between site pairs. Results show an overall
inverse relationship between particle size and CODs, implying that number
concentrations of smaller particles (<40 nm) differ from site to site,
whereas larger particles tend to have similar concentrations at various
sampling locations. In addition, variations in r values as a function of
particle size are not necessarily consistent with corresponding COD values,
indicating that using results from correlation analysis alone may not
accurately assess spatial variability. |
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