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| Titel |
Heated submicron particle fluxes using an optical particle counter in urban environment |
| VerfasserIn |
M. Vogt, C. Johansson, M. Mårtensson, H. Struthers, L. Ahlm, D. Nilsson |
| 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 (2013-03-15), S.3087-3096 |
| Datensatznummer |
250018519
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| Publikation (Nr.) |
 copernicus.org/acp-13-3087-2013.pdf |
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| Zusammenfassung |
| From May 2008 to March 2009 aerosol emissions were measured using the eddy
covariance method covering the size range 0.25 to 2.5 μm diameter
(Dp) from a 105 m tower, in central Stockholm, Sweden.
Supporting chemical aerosol data were collected at roof and street level.
Results show that the inorganic fraction of sulfate, nitrate, ammonium and
sea salt accounts for approximately 15% of the total aerosol mass
< 1 μm Dp (PM1) with water soluble soil contributing
11% and water insoluble soil 47%. Carbonaceous compounds were at
the most 27% of PM1 mass. It was found that heating the air from
the tower to 200 °C resulted in the loss of approximately
60% of the aerosol volume at 0.25 μm Dp whereas only
40% of the aerosol volume was removed at 0.6 μm Dp.
Further heating to 300 °C caused very little additional losses
<0.6 μm Dp. The chemical analysis did not include
carbonaceous compounds, but based on the difference between the total mass
concentration and the sum of the analyzed non-carbonaceous materials, it can
be assumed that the non-volatile particulate material (heated to
300 °C) consists mainly of carbonaceous compounds, including
elemental carbon. Furthermore, it was found that the non-volatile particle
fraction <0.6 μm Dp correlated (r2 = 0.4) with the
BC concentration at roof level in the city, supporting the assumption that
the non-volatile material consists of carbonaceous compounds. The average
diurnal cycles of the BC emissions from road traffic (as inferred from the
ratio of the incremental concentrations of nitrogen oxides (NOx)
and BC measured on a densely trafficked street) and the fluxes of
non-volatile material at tower level are in close agreement, suggesting a
traffic source of BC. We have estimated the emission factors (EFs) for
non-volatile particles <0.6 μm Dp to be
2.4 ± 1.4 mg veh−1 km−1 based on either CO2
fluxes or traffic activity data. Light (LDV) and heavy duty vehicle (HDV) EFs
were estimated using multiple linear regression and reveal that for
non-volatile particulate matter in the 0.25 to 0.6 μm Dp
range, the EFHDV is approximately twice as high as the
EFLDV, the difference not being statistically significant. |
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