1. Summertime particulate matter and its composition in GreeceM. A. Tsiflikiotou, E. Kostenidou, D. K. Papanastasiou, D. Patoulias, Pavlos Zarmpas, D. Paraskevopoulou, E. Diapouli, Christos Kaltsonoudis, Kalliopi Florou, Iasonas Stavroulas, 2019, izvirni znanstveni članek Opis: During the summer of 2012 a coordinated field campaign was conducted in multiple locations in Greece in order to characterize the ambient particulate matter (PM) levels, its chemical composition and the contribution of the regional and local sources. PM1, PM2.5 and PM10 samples were collected simultaneously at seven different sites in Greece: an urban and a suburban station in Patras, a suburban station in Thessaloniki, a suburban and an urban background station in Athens, a rural background station at the Navarino Environmental Observatory (NEO) in southwestern Peloponnese and a remote background site at Finokalia in the northeastern part of Crete. The sites were selected to facilitate the estimation of the contribution of the local emission sources and long range transport.
Sulfate and organics were the major PM1 components in all sites suggesting that high sulfate levels still remain in parts of Europe. The photochemistry of the Eastern Mediterranean can convert rapidly the emitted sulphur dioxide to sulfate. Our analysis indicated significant sulfate production over the area, with high sulfate levels, especially in the remote site of Finokalia, associated with air masses that had passed over Turkey. There was high regional secondary organic aerosol production dominating organic aerosol levels even in a major city like Athens. High organic aerosol levels were associated with air masses that had crossed the Balkans with a significant biogenic component. The average PM2.5 concentration ranged from 13 to 18 μg m−3 in the different sites. There were unexpected significant gradients in the concentrations of secondary aerosol components in length scales of a few hundred kilometers. The low concentrations of measured PM2.5 nitrate are mostly organic nitrates and supermicrometer nitrate associated with sea-salt and dust. Dust was a significant PM10 constituent in all areas and was quite variable in space showing the importance of the local sources.
Ključne besede: PM2.5, sulfate aerosol, secondary inorganic aerosol, secondary organic aerosol, Greece
Objavljeno v RUNG: 13.05.2024; Ogledov: 136; Prenosov: 0
Gradivo ima več datotek! Več... |
2. Development and evaluation of an improved offline aerosol mass spectrometry techniqueChristina Vasilakopoulou, Kalliopi Florou, Christos Kaltsonoudis, Iasonas Stavroulas, Nikolaos Mihalopoulos, Spyros N. Pandis, 2023, izvirni znanstveni članek Opis: Abstract. The offline aerosol mass spectrometry technique is
a useful tool for the source apportionment of organic aerosol (OA) in areas
and periods during which an aerosol mass spectrometer (AMS) is not available. However, the technique is
based on the extraction of aerosol samples in water, while several
atmospheric OA components are partially or fully insoluble in water. In this work an improved offline technique was developed and evaluated in an effort to capture most of the partially soluble and insoluble organic aerosol material, reducing significantly the uncertainty of the corresponding source
apportionment. A major advantage of the proposed approach is that no
corrections are needed for the offline analysis to account for the limited
water solubility of some OA components. The improved offline AMS analysis
was tested in three campaigns: two during winter and one during summer.
Collocated online AMS measurements were performed for the evaluation of the offline method. Source apportionment analysis was performed separately for the online and the offline measurements using positive matrix
factorization (PMF). The PMF results showed that the fractional contribution of each factor to the total OA differed between the online and the offline PMF results by less than 15 %. The differences in the AMS spectra of the
factors of the two approaches could be significant, suggesting that the use
of factor profiles from the literature in the offline analysis may lead to
complications. Part of the good agreement between the online and the
offline PMF results is due to the ability of the improved offline AMS
technique to capture a bigger part of the OA, including insoluble organic
material. This was evident by the significant fraction of submicrometer
suspended insoluble particles present in the water extract and by the
reduced insoluble material on the filters after the extraction process. More than half of the elemental carbon (EC) was on average missing from the
filters after the water extraction. Significant EC concentrations were
measured in the produced aerosol that was used as input to the AMS during
the offline analysis.
Ključne besede: organic aerosol, receptor modeling, offline PMF, Greece
Objavljeno v RUNG: 10.05.2024; Ogledov: 130; Prenosov: 2
 Povezava na datoteko
Gradivo ima več datotek! Več... |
