 |
| Titel |
Differences in aerosol absorption Ångström exponents between correction algorithms for a particle soot absorption photometer measured on the South African Highveld |
| VerfasserIn |
J. Backman, A. Virkkula, V. Vakkari, J. P. Beukes, P. G. Van Zyl, M. Josipovic, S. Piketh, P. Tiitta, K. Chiloane, T. Petäjä, M. Kulmala  , L. Laakso |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1867-1381
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 12 ; Nr. 7, no. 12 (2014-12-08), S.4285-4298 |
| Datensatznummer |
250115985
|
| Publikation (Nr.) |
 copernicus.org/amt-7-4285-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| Absorption Ångström exponents (AAEs) calculated from filter-based
absorption measurements are often used to give information on the origin of
the ambient aerosol, for example, to distinguish between urban pollution and
biomass burning aerosol. Filter-based absorption measurements are widely
used and are common at aerosol monitoring stations globally. Several
correction algorithms are used to account for artefacts associated with
filter-based absorption techniques. These algorithms are of profound
importance when determining the absolute amount of absorption by the
aerosol. However, this study shows that there are substantial differences
between the AAEs calculated from these corrections. Depending on the used
correction, AAEs can change by as much as 46%. The study also highlights
that the difference between AAEs calculated using different corrections can
lead to conflicting conclusions on the type of aerosol when using the same
data set. The AAE ranged between 1.17 for non-corrected data to 1.96 for the
correction that gave the greatest values. Furthermore, the study implies
that the AAEs reported for a site depend on at which filter transmittance
the filter is changed. In this work, the AAEs were calculated from data
measured with a three-wavelength particle soot absorption photometer (PSAP)
at Elandsfontein on the South African Highveld for 23 months. The sample air
of the PSAP was diluted to prolong filter change intervals, by a factor of
15. The correlation coefficient between the dilution-corrected PSAP and a
non-diluted Multi-Angle Absorption Photometer (MAAP) was 0.9. Thus, the
study also shows that the applicability of the PSAP can be extended to
remote sites that are not often visited or suffer from high levels of
pollution. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|