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Identifier

000461539

Title

Μελέτη της κατανομής μεγέθους υπέρλεπτων σωματιδίων και ιόντων στην ατμόσφαιρα της Ανατολικής Μεσογείου

Alternative Title

Study of the size distributions of submicron aerosols and ions in the East Mediterranean atmosphere

Author

Μαρκουλάκης, Σπυρίδων Εμμανουήλ Ν.

Thesis advisor

Κανακίδου, Μαρία

Reviewer

Μιχαλόπουλος, Νικόλαος
Περγαντής, Σπυρίδων

Abstract

New particle formation (NPF) is a common phenomenon in the atmosphere that takes place globally. In this study, size distributions of ultrafine particles and ions were investigated using a Neutral Air Ion Spectrometer (NAIS). The measurements were performed at the Finokalia environmental research station of the University of Crete (35^o 20' N, 25^o 40' E, 250 m asl) (https://finokalia.chemistry.uoc.gr ), in Crete, Greece in the eastern Mediterranean during a two years period from June 2020 to May 2022. Size distribution data were available for 468 measurement days that were classified as follows. NPF events were observed in 40% of the days, non-event days were 38% of the total measurement days and the remaining 22% were undefined cases. NPF days were more common during the winter due to the low concentrations of pre-existing particles and the resulting low condensation sink (CS). On the other hand, non-event days were more common during the warmest months of the year, especially July and August. Finally, the days with undefined cases showed no clear seasonal pattern. In order to calculate the relative contribution of ions to the total particle formation, data from a twoyear time series of number concentrations of small (0.8-1.6 nm), intermediate (1.6-7.4 nm), and large ions (7.4-25 nm) were studied. From the ion time series, a strong anti-correlation was demonstrated between small ions and condensation and coagulation sinks. For the intermediate size fraction of ions, a correlation between intermediate ion number concentration and NPF events was found, as the intermediate ions are a strong indicator of new particle formation bursts. Finally, for large ions, the maximum number concentration appeared 2 hours after that of the intermediate ions, probably resulting from the growth of intermediate to large ions. As for the non-event days, by normalizing the ion size distributions, it was shown that the formation of new particles is also observed on these days. This phenomenon, which was called Quiet NPF by Kulmala et al (2022), appears to significantly contribute to the new particle formation in the atmosphere.

Language

Greek

Subject

Air ions

NPF events

Secondary particles

Αερολύματα

Ατμοσφαιρικά ιόντα

Δευτερογενή σωματίδια

Κατανομές μεγέθους

Φαινόμενα σχηματισμού νέων σωματιδίων

Issue date