Chemistry Reference
In-Depth Information
Fig. 3 PM
10
measurements at Heraklion during the period November 2001-September 2005 [
31
]
an overall decrease of the PM
10
annual average concentrations is observed at the
urban monitoring stations in Thessaloniki from 2001 to 2010 [
30
]. Again for
Thessaloniki urban area could be argued that the employed abatement strategies
combined with the financial crisis led to the reduction of particulate matter.
Results from PM studies conducted in other urban areas in Greece conclude that
PM levels have similar values with moderately polluted sites worldwide [
31
,
32
].
Gerasopoulos et al. [
31
] report on the concentration levels of PM
10
in the urban area
of Heraklion (Crete Island, Greece) during 2001-2005, Fig.
3
. In this urban site the
average value of PM
10
is 51
g/m
3
while after 2003 the exceedances of the
established limit values were more frequent with this phenomenon being attributed
to the heat wave that influenced central Europe in summer 2003 and to the frequent
Saharan dust intrusions.
Partial information is available concerning the aerosol composition over the
Eastern Mediterranean since most of the studies conducted in the region report
only on specific compounds (e.g: inorganic ions, metals, alkanes, PAHs) and do not
provide the complete characterisation of aerosols. In urban sites of Greece water-
soluble inorganic ions, mainly sulphate, dominate the PM mass and might contrib-
ute up to 60% of the PM
10
mass followed by mineral dust components and
carbonaceous matter [
17
,
21
,
31
,
33
,
34
]. The high sulphate loadings in the EMB
are mostly attributed to long-range transport of pollution sources. In fact a 4-year
aerosol study carried out at Thessaloniki by means of a Raman lidar indicated
higher aerosol optical depth values and backscatter ratio mostly corresponding to air
masses originating from the northeast Balkans and Eastern Europe [
35
].
m
5 Source Contribution in the Eastern Mediterranean Basin
Table
1
lists a number of studies carried out in urban sites of the Eastern Mediter-
ranean Basin that have used multivariate statistical methods to quantify the mass
contribution of sources of particulate matter. In most of these studies, four or five
major source categories have been detected. These categories include road/soil
dust, traffic emissions, marine aerosol, fuel oil combustion emissions, biomass
