Chemistry Reference
In-Depth Information
Fig. 8 Features of Eastern Mediterranean Finokalia size distributions. Location of the station is
shown in the
inset
The station had greatest N
30-50
concentrations during spring and winter with no
apparent day/night difference. The concentration levels were relatively low, with a
median concentration of 220 cm
3
.
The particle histograms show peaks in N
50
and N
100
concentrations during
spring of over 1,000 particles cm
3
. Another smaller mode of low concentrations
was also visible around 500 particles cm
3
in both N
50
and N
100
.
3.3 Correlations Between Aitken and Accumulation Mode
Figure
9
(adapted from [
18
]) shows some of the typical correlations between
particle number concentrations between 30 and 100 nm (here referred to as “Aitken
mode,” although a more rigorous derivation would require actual modal fitting) and
concentrations between 100 and 500 nm (“accumulation mode”). The idea of this
kind of plot is to show the possible correlation between the two aerosol modes, to
indentify some of the main particle number size distribution types, and whether the
particle number concentrations in both modes increase in the same rate.
In general, the Aitken and accumulation mode number concentrations are
correlating (on logarithmic scales), but on different environments, the correlation
is not always along the 1:1 line. Aerosol at the Nordic, Mediterranean and polluted
continental (Central European) conditions has roughly distributions along the
diagonal, which shows that in most cases the Aitken and accumulation modes are
behaving in the same way. This suggests that the shape of the particle number size
distribution is relatively nonsensitive to the overall concentration levels. In contrast,
the free tropospheric part of the mountain distributions is almost round in shape, a
