Volume 12 - 2010

An artificial neural network (ANN) model-based approach was developed and applied to estimate
values of air temperature and relative humidity in remote mountainous areas. The application site
was the mountainous area of the Samaria National Forest canyon (Greece). Seven meteorological
stations were established in the area and ANNs were developed to predict air temperature and
relative humidity for the five most remote stations of the area using data only from two stations
located in the two more easily accessed sites. Measured and model-estimated data were compared
in terms of the determination coefficient (R2), the mean absolute error (MAE) and residuals
normality. Results showed that R2 values range from 0.7 to 0.9 for air temperature and from 0.7 to
0.8 for relative humidity whereas MAE values range from 0.9 to 1.8 oC and 5 to 9%, for air
temperature and relative humidity, respectively. In conclusion, the study demonstrated that ANNs,
when adequately trained, could have a high applicability in estimating meteorological data values in
remote mountainous areas with sparse network of meteorological stations, based on a series of
relatively limited number of data values from nearby and easily accessed meteorological stations.

Human thermal comfort conditions were determined in two mountainous regions of Greece, Gerania
mountains (MG) in east continental Greece, and mountainous Nafpaktia (MN) in west continental
Greece. Both regions are unexploited with considerable tourist potential. Four sites in each study
region were selected on the basis of different altitude. Air temperature and humidity, 1.5 m above
ground surface, were recorded simultaneously every 15 minutes by sensors with dataloggers in
selected sites between 23 June and 28 August 2007. Data of the above parameters were used for
the calculation of the thermohygrometric index from which thermal comfort conditions were
evaluated. Also, an artificial neural network model, was applied for the THI values evaluation at the
highest examined altitudes based on the respective values of the lowest examined altitudes in both
MG and MN. Results showed that from 09:00 to 20:00 h, MN was found to be more suitable, in
relation to MG, for tourist and recreation activities at altitudes of 1338 m. At lower altitudes, both
study regions could be proposed in an equal basis for the above activities during summer. Also, for
the same period, thermal comfort conditions at the highest examined altitudes of MN and MG can
accurately be predicted using artificial neural network models on the basis of those at lowest
examined altitudes. From 21:00 to 08:00 h, MN can be considered clearly as a better tourist
destination than MG.

Although solar salterns worldwide use seawater of identical chemical composition as the raw
material for salt production, the size and quality of the halite crystals that precipitate in the
crystallizer ponds is highly variable. Biological processes have been implicated to be responsible for
the differences observed, but the “missing link” between saltworks biology and solar salt quality has
never unequivocally been identified. This paper presents an overview of the different organic
chemicals that are formed by the members of the microbial communities in saltern evaporation and
crystallizer ponds as osmotic stabilizers as well as different compounds formed during further
microbial metabolism of those osmotic solutes. Examination of the in situ concentrations and the
possible role of glycerol, glycine betaine, ectoine, dihydroxyacetone, acetate, lactate, and other
organic compounds failed to identify one or more compounds that may accumulate at concentrations
high enough to significantly modify the formation of sodium chloride crystals in the salterns and to
negatively influence the quality of the salt produced.

The aim of the present work was to characterize particulate matter (PM) and elemental
carbon (EC) indoor and outdoor concentration levels in the Athens area and to examine the
contribution of ambient air to the observed indoor levels.
24-hr simultaneous indoor and outdoor PM10 and PM2.5 measurements were conducted at a
central (CR) and a suburban (SR) residence, and at an office in the commercial centre of
Athens (CO), during cold and warm period of 2006. The absorption coefficient (α) was
measured on the collected filters, as a surrogate for EC concentration levels.
Ambient PM levels were very high at both central sites and significant at SR (mean 24-hr
PM10: 87.4, 50.3 and 87.3 μg m-3 and PM2.5: 50.7, 20.2 and 42.8 μg m-3 at CR, SR and CO).
The measured absorption coefficient values were very high at CR and CO for both size
fractions.
Indoor PM concentration and absorption coefficient values were lower than the respective
outdoor ones, but still significant at the two central sites.
Very good correlations were observed between indoor and outdoor data (especially for
absorption coefficient values), indicating a large contribution of the ambient atmosphere to the
indoor levels, more pronounced in finer particles.