Mass and chemical composition of size-segregated aerosols (PM1, PM2.5, PM10) over Athens, Greece: local versus regional sources 1Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, P.O. Box 2208, 71003 Heraklion, Greece
30 Nov 2011
2School of Chemical engineering, National Technical University of Athens, Heroon Polytechniou 9, 15780 Zografou, Athens, Greece
Received: 07 Dec 2010 – Published in Atmos. Chem. Phys. Discuss.: 04 Mar 2011Abstract. To identify the relative contribution of local versus regional sources of
particulate matter (PM) in the Greater Athens Area (GAA), simultaneous 24-h
mass and chemical composition measurements of size segregated particulate
matter (PM1, PM2.5 and PM10) were carried out from September
2005 to August 2006 at three locations: one urban (Goudi, Central Athens,
"GOU"), one suburban (Lykovrissi, Athens, "LYK") in the GAA and one at a
regional background site (Finokalia, Crete, "FKL").
Revised: 04 Sep 2011 – Accepted: 12 Nov 2011 – Published: 30 Nov 2011
The two stations in the GAA exceeded the EU-legislated PM10 limit
values, both in terms of annual average (59.0 and 53.6 μg m−3 for
Lykovrissi and Goudi, respectively) and of 24-h value. High levels of
PM2.5 and PM1 were also found at both locations (23.5 and 18.6 for
Lykovrissi, while 29.4 and 20.2 μg m−3 for Goudi, respectively).
Significant correlations were observed between the same PM fractions at both
GAA sites indicating important spatial homogeneity within GAA. During the
warm season (April to September), the PM1 ratio between GAA and FKL
ranged from 1.1 to 1.3. On the other hand this ratio was significantly
higher (1.6–1.7) during the cold season (October to March) highlighting
the role of long-range transport and local sources during the warm and cold
seasons respectively. Regarding the coarse fraction no seasonal trend was
observed for both GAA sites with their ratio (GAA site/FKL) being higher
than 2 indicating significant contribution from local sources such as soil
and/or road dust.
Chemical speciation data showed that on a yearly basis, ionic and crustal
mass represent up to 67–70% of the gravimetrically determined mass for
PM10 samples in the GAA and 67% for PM1 samples in LYK. The
unidentified mass might be attributed to organic matter (OM) and elemental
carbon (EC), in agreement with the results reported by earlier studies in
central Athens. At all sites, similar seasonal patterns were observed for
nss-SO42−, a secondary compound, indicating significant
contribution from regional sources in agreement with PM1 observations.
The contribution of local sources at both GAA sites was also estimated by
considering mass and chemical composition measurements at Finokalia as
representative of the regional background. Particulate Organic Matter (POM)
and EC, seemed to be the main contributor of the local PM mass within the
GAA (up to 62% in PM1. Dust from local sources contributed also
significantly to the local PM10 mass (up to 33%).
Citation: Theodosi, C., Grivas, G., Zarmpas, P., Chaloulakou, A., and Mihalopoulos, N.: Mass and chemical composition of size-segregated aerosols (PM1, PM2.5, PM10) over Athens, Greece: local versus regional sources, Atmos. Chem. Phys., 11, 11895-11911, doi:10.5194/acp-11-11895-2011, 2011.