 |
| Titel |
Characterisation of sub-micron particle number concentrations and formation events in the western Bushveld Igneous Complex, South Africa |
| VerfasserIn |
A. Hirsikko, V. Vakkari, P. Tiitta, H. E. Manninen, S. Gagné, H. Laakso  , M. Kulmala , A. Mirme, S. Mirme, D. Mabaso, J. P. Beukes, L. Laakso |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 9 ; Nr. 12, no. 9 (2012-05-04), S.3951-3967 |
| Datensatznummer |
250011113
|
| Publikation (Nr.) |
 copernicus.org/acp-12-3951-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| South Africa holds significant mineral resources, with a substantial
fraction of these reserves occurring and being processed in a large
geological structure termed the Bushveld Igneous Complex (BIC). The area is
also highly populated by informal, semi-formal and formal residential
developments. However, knowledge of air quality and research related to the
atmosphere is still very limited in the area. In order to investigate the
characteristics and processes affecting sub-micron particle number
concentrations and formation events, air ion and aerosol particle
size distributions and number concentrations, together with meteorological
parameters, trace gases and particulate matter (PM) were measured for over
two years at Marikana in the heart of the western BIC. The observations
showed that trace gas (i.e. SO2, NOx, CO) and black carbon
concentrations were relatively high, but in general within the limits of
local air quality standards. The area was characterised by very high
condensation sink due to background aerosol particles, PM10 and O3
concentration. The results indicated that high amounts of Aitken and
accumulation mode particles originated from domestic burning for heating and
cooking in the morning and evening, while during daytime SO2-based
nucleation followed by the growth by condensation of vapours from
industrial, residential and natural sources was the most probable source for
large number concentrations of nucleation and Aitken mode particles.
Nucleation event day frequency was extremely high, i.e. 86% of the
analysed days, which to the knowledge of the authors is the highest
frequency ever reported. The air mass back trajectory and wind direction
analyses showed that the secondary particle formation was influenced both by
local and regional pollution and vapour sources. Therefore, our observation
of the annual cycle and magnitude of the particle formation and growth rates
during nucleation events were similar to results previously published for a
semi-clean savannah site in South Africa. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|