In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 23, No. 5 ( 2023-03-08), p. 3051-3064
Abstract:
Abstract. Soot, or black carbon (BC), aerosol is a major climate
forcer with severe health effects. The impacts depend strongly on particle
number concentration, size and mixing state. This work reports on two field
campaigns at nearby urban and rural sites, 65 km apart, in southern Sweden
during late summer 2018. BC was measured using a single-particle soot
photometer (SP2) and Aethalometers (AE33). Differences in BC concentrations
between the sites are driven primarily by local traffic emissions.
Equivalent and refractory BC mass concentrations at the urban site were on
average a factor 2.2 and 2.5, with peaks during rush hour up to a factor
∼4, higher than the rural background levels. The number
fraction of particles containing a soot core was significantly higher in the
city. BC particles at the urban site were on average smaller by mass and had
less coating owing to fresh traffic emissions. The organic components of the
fresh traffic plumes were similar in mass spectral signature to
hydrocarbon-like organic aerosol (HOA), commonly associated with
traffic. Despite the intense local traffic (∼ 30 000 vehicles
passing per day), PM1, including organic aerosol, was dominated by aged
continental air masses even at the curbside site. The fraction of thickly
coated particles at the urban site was highly correlated with the mass
concentrations of all measured chemical species of PM1, consistent with
aged, internally mixed aerosol. Trajectory analysis for the whole year
showed that air masses arriving at the rural site from eastern Europe
contained approximately double the amount of BC compared to air masses from
western Europe. Furthermore, the largest regional emissions of BC transported to the rural site, from the Malmö–Copenhagen urban area, are discernible above background levels only when precipitation events are excluded. We show
that continental Europe and not the Malmö–Copenhagen region is the
major contributor to the background BC mass concentrations in southern
Sweden.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-23-3051-2023
DOI:
10.5194/acp-23-3051-2023-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2023
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
