Publications

The aim of this study was to explore particle size dependent properties by combining long-term observations
of equivalent black carbon (eBC) and number size distributions to investigate their correlation as function of
particle size. The work was conducted in two main parts. The first part consisted of a short laboratory
experiment to compare observed total particle light absorption (sigma_abs) with that observed according to particle
size by using a combination of a Differential Mobility Analyzer (DMA) and a Particle Soot Absorption
Photometer (PSAP). The laboratory study confirmed strong similarities between the observed and derived
r abs . In the second part the statistical approach using correlation between the r abs and the dN of each bin of
the number size distribution was tested on long-term data ranging from 2002 to 2010 observed at Zeppelin
station, Ny-Ålesund Svalbard. The data was clustered according to the number size distribution and grouped
in four major categories: Washout, Nucleation, Intermediate and Polluted. Each category presented different
features with respect to the derived eBC mass distributions, the Intermediate category showed similarities to
the few available Single Particle Soot Photometer (SP2) observations in the Arctic. Overall, the statistical
distribution of eBC, according to particle size, presented a larger dynamical range in the location of the
mode(s). To check for consistency, the eBC mass distributions were transformed into number based eBC size
distribution and compared to the observed total number size distribution. Whereas the Washout, Nucleation
and Intermediate categories presented plausible number distributions, the Polluted category displayed a mode
at small sizes (about 50nm) that was significantly exaggerated