Atmospheric PM10 particle concentration measurements at central and peripheral urban sites in Athens and Thessaloniki, Greece

The analysis of the PM10 particle measurements at the two major urban areas of Greece,
Athens and Thessaloniki, showed that the mean monthly PM10 concentrations at the central
urban stations, are on the average about twice as high than the corresponding ones at the
examined peripheral stations. The distribution of the daily PM10 values shows significant
violations of the EU air quality standards, especially in the central urban stations. At the
peripheral stations comparable distributions of PM10 concentration values are found. The
highest PM10 hourly values are recorded at the central urban stations during the cold
semester of the year and during the morning hours. The scatter-plot diagrams of the central
urban daily PM10 mean values versus the peripheral stations show important influence of the
regional aerosol episodes on the measured PM10 concentrations in the urban areas of Athens
and Thessaloniki, which is stronger in Athens and during the warm semester of the year. The
PM10 diurnal variation pattern are quite similar with the corresponding variations observed for
primary urban pollutants, like the morning and the evening peaks, but also at the peripheral
stations exhibit a broad mid-day peak indicating elevated rural background PM10 levels.
Additional daily measurements at the rural station of Aliartos in Central Greece give PM10
average values around 30 μg m-3, comparable to the corresponding average PM10 values of
the peripheral stations in Athens and Thessaloniki. Such high rural background PM10 daily
mean values could lead to average annual values higher than the corresponding EU PM10
standard (40 μg m-3) and should be taken into account in the formulation of the local pollution
abatement strategies as they represent about the half of the average PM10 levels measured at
the central urban stations of both examined urban areas.