Chemistry Reference
In-Depth Information
(Crete Island) showed that long-range transport of agricultural waste burning from
European countries surrounding the Black Sea occurred twice a year (March-April
and July-September). The contribution of biomass burning to the concentrations of
EC and OC was shown to be rather small (20% and 14%, respectively, on a yearly
basis), although this contribution could be much higher on a monthly basis and
showed important seasonal and interannual variability.
The study of Amiridis et al. [
47
] demonstrated that the smoke plume from the
fires in Athens during the summer of 2009 was distributed homogenously within the
Planetary Boundary Layer of Athens, reaching in some cases free troposphere
heights (2-4 km). Both columnar aerosol retrievals and surface measurements
revealed the dominance of fine over coarse mode. Regarding PM
10
and PM
2.5
urban background levels showed an increase of about 100% and 150% during the
fires, demonstrating the dominance of fine particles near the surface due to the fire
plume. The signature of the smoke plume was characterised by the high concentra-
tion levels of carbonaceous aerosol both EC and OC. During the forest fires, more
OC than EC is emitted, resulting in a relatively higher OC/EC ratio. At Athens
urban background site the average OC/EC ratio ranged between 10 and 14 during
the forest fires while in normal conditions was about 4 [
47
].
5.4 Shipping Emissions
About 70% of the emissions from oceangoing shipping occur within 400 km of the
coastlines along the main trade routes. Thereby, ship emissions can have an impact
on the air quality in coastal regions and may partly offset the decline of land-based
sources and coastal pollution due to national control measures [
48
]. In coastal urban
areas, emissions from commercial shipping (passenger and cargo) may also consti-
tute a relevant source of PM and SO
2
emissions [
49
]. According to global estimates,
shipping emits between 0.9 and 1.7 million tonnes of total suspended particles
(TSP) annually that mainly contain organic carbon, sulphate and inorganic
constituents (V, Ni, Ca, Fe) [
50
].
The Mediterranean Basin is highly influenced by shipping emissions due to its
extremely busy shipping routes. These emissions may account for 2-4% of the
mean annual ambient air PM
10
levels (25% primary particles and 75% secondary
particles) and for 14% of the mean annual PM
2.5
in Mediterranean urban areas [
51
].
It has been estimated that 54% of the total sulphate aerosol column burden over the
Mediterranean in summer originates from ship emissions [
52
].
Greece is found to be a major and growing contributor of exhaust emissions from
domestic and international shipping. Through 1984-2008, the ship emission inven-
tory for Greece had an almost fourfold increase. In particular, the PM emissions
from domestic and international shipping have an increasing trend that reached 24
million tonnes in 2008 (Fig.
5
). Greece contributes to the European and Mediterra-
nean emission inventory from shipping with 7.3% and 14.1%, respectively [
53
].
Studies on ship emissions have been carried out mainly in harbour areas and
coastal cities in the Western Mediterranean Basin by aerosol chemical analysis and
