Characterization of African dust over southern Italy

Blanco, A.; Tomasi, F. Dee; Filippo, Emanuela; Manno, D.; Perrone, Maria Rita; Serra, A.; Tafuro, A. M.; Tepore, A.

doi:10.5194/acp-3-2147-2003

Cited by 86 publications

(66 citation statements)

References 42 publications

(57 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Furthermore, these particles often have rounded morphologies or chamfered edges, and consist mainly of clay minerals (smectite, kaolinite and illite/mica in variable proportions) and quartz, which are the main components of atmospheric Saharan dust (e.g. Krueger et al, 2004;Brooks et al, 2005;Coz et al, 2009;. Particularly, on these dates the highest amounts of quartz were detected (Figs.…”

Section: Discussionmentioning

confidence: 99%

“…Al / Si ratios > 0.3 are generally considered indicators of desert dust (Molinaroli, 1996;Guerzoni et al, 1997;Blanco et al, 2003;Kandler et al, 2007;Matassoni et al, 2011), however Coude-Gaussen et al (1987) have already found that the Al / Si ratio can vary with particle size. They noted that finest fractions have an Al / Si ratio significantly lower than that of mean aerosols, with values below 0.3, due to larger amounts of quartz.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

PM<sub>1</sub> geochemical and mineralogical characterization using SEM-EDX to identify particle origin – Agri Valley pilot area (Basilicata, southern Italy)

Margiotta

Lettino

Speranza

et al. 2015

Nat. Hazards Earth Syst. Sci.

View full text Add to dashboard Cite

Abstract.A PM 1 geochemical and mineralogical study using Scanning Electron Microscopy (SEM) was performed on a pilot site in the Agri Valley which is close to the oil pre-treatment plant (C.O.V.A) of Europe's largest on-shore hydrocarbon reservoir. The study identified PM 1 geochemical and mineralogical characters in the period before, during and immediately after a burning torch flare event. The finer fraction (D Fe < 0.7 µm) consisted mainly of secondary particles and soot. In the coarser fraction (D Fe ≥ 0.7 µm), natural particles originating from crustal erosion and soot were abundant. Fine quartz particles and lower Al / Si ratios are markers for desert dust origin, proving that a Saharan dust episode which occurred during the observation period played a significant role in supplying geogenic aerosol components to the PM 1 . Largest amounts of ≥ 0.7 µm fraction particles observed on the day of flare event may be due to a greater supply of Saharan geogenic particles. Soot had been significantly increasing long before the flare event, suggesting that this increase is also related to other causes, although we cannot exclude a contribution from flaring. S-rich aerosol consisted mainly of mixed particles originating from deposition and heterogeneous nucleation of secondary sulfates on mineral dust. Only-S particles were identified in the ≥ 0.7 µm fraction following the flare event. These particles may be indicators of larger amounts of sulphur in the atmosphere.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

PM<sub>1</sub> geochemical and mineralogical characterization using SEM-EDX to identify particle origin – Agri Valley pilot area (Basilicata, southern Italy)

Margiotta

Lettino

Speranza

et al. 2015

Nat. Hazards Earth Syst. Sci.

View full text Add to dashboard Cite

show abstract

“…Single particle analysis of mineral dust employing SEM-EDXS analysis is basically qualitative because of the irregular shape and wide size range of dust particles (Blanco et al, 2003;Kandler et al, 2007;Fletcher et al, 2011). In addition, the dust particles are mostly the agglomerates of subgrains of wide-ranging mineralogy and size in varying ratios.…”

Section: Dust Samples and Methodsmentioning

confidence: 99%

Long-range transport of giant particles in Asian dust identified by physical, mineralogical, and meteorological analysis

et al. 2014

View full text Add to dashboard Cite

Abstract. Giant particles transported over long distances are generally of limited concern in atmospheric studies due to their low number concentrations in mineral dust and possible local origin. However, they can play an important role in regional circulation of earth materials due to their enormous volume concentration. Asian dust laden with giant particles was observed in Korea on 31 March 2012, after a migration of about 2000 km across the Yellow Sea from the Gobi Desert. Scanning electron microscopy (SEM) revealed that 20 % of the particles exceeded 10 µm in equivalent sphere diameter, with a maximum of 60 µm. The median diameter from the number distribution was 5.7 µm, which was larger than the diameters recorded of 2.5 and 2.9 µm in Asian dust storms in 2010 and 2011, respectively, and was consistent with independent optical particle counter data. Giant particles (> 10 µm) contributed about 89 % of the volume of the dust in the 2012 storm. Illite-smectite series clay minerals were the major mineral group followed by quartz, plagioclase, K-feldspar, and calcite. The total phyllosilicate content was ∼52 %. The direct long-range transport of giant particles was confirmed by calcite nanofibers closely associated with clays in a submicron scale identified by high-resolution SEM and transmission electron microscopy. Since giant particles consisted of clay agglomerates and clay-coated quartz, feldspars, and micas, the mineral composition varied little throughout the fine (< 5 µm), coarse (5-10 µm), giant-S (10-20 µm), and giant-L (> 20 µm) size bins. Analysis of the synoptic conditions of the 2012 dust event and its migration indicated that the mid-tropospheric strong wind belt directly stretching to Korea induced rapid transport of the dust, delivering giant particles. Giant dust particles with high settling velocity would be the major input into the terrestrial and marine sedimentary and ecological systems of East Asia and the western Pacific. Analysis of ancient aeolian deposits in Korea suggested the common deposition of giant particles from Asian dust through the late Quaternary Period. The roles of giant particles should be reviewed with regard to regional circulation of mineral particles and nutrients.

show abstract

“…Desert dust aerosols are mainly composed of varying shares of illite, kaolinite and montmorillonite (Kumai, 1961;Kumai and Francis, 1962;O'Hara et al, 2006;Zimmermann et al, 2008;Chudnovsky et al, 2009) depending on the source region (Avila et al, 1997;Ganor, 1991;Blanco et al, 2003;Moreno et al, 2006). These clay minerals have frequently been used as mineral dust surrogates in ice freezing experiments and their ability to act as IN is well established.…”

Section: Pinti Et Al: Ice Nucleation Efficiency Of Clay Mineralsmentioning

confidence: 99%

Ice nucleation efficiency of clay minerals in the immersion mode

et al. 2012

View full text Add to dashboard Cite

Abstract. Emulsion and bulk freezing experiments were performed to investigate immersion ice nucleation on clay minerals in pure water, using various kaolinites, montmorillonites, illites as well as natural dust from the Hoggar Mountains in the Saharan region. Differential scanning calorimeter measurements were performed on three different kaolinites (KGa-1b, KGa-2 and K-SA), two illites (Illite NX and Illite SE) and four natural and acid-treated montmorillonites (SWy-2, STx-1b, KSF and K-10). The emulsion experiments provide information on the average freezing behaviour characterized by the average nucleation sites. These experiments revealed one to sometimes two distinct heterogeneous freezing peaks, which suggest the presence of a low number of qualitatively distinct average nucleation site classes. We refer to the peak at the lowest temperature as "standard peak" and to the one occurring in only some clay mineral types at higher temperatures as "special peak". Conversely, freezing in bulk samples is not initiated by the average nucleation sites, but by a very low number of "best sites". The kaolinites and montmorillonites showed quite narrow standard peaks with onset temperatures 238 K < T std on < 242 K and best sites with averaged median freezing temperature T best med = 257 K, but only some featuring a special peak (i.e. KSF, K-10, K-SA and SWy-2) with freezing onsets in the range 240-248 K. The illites showed broad standard peaks with freezing onsets at 244 K < T std on < 246 K and best sites with averaged median freezing temperature T best med = 262 K. The large difference between freezing temperatures of standard and best sites shows that characterizing ice nucleation efficiencies of dust particles on the basis of freezing onset temperatures from bulk experiments, as has been done in some atmospheric studies, is not appropriate. Our investigations demonstrate that immersion freezing temperatures of clay minerals strongly depend on the amount of clay mineral present per droplet and on the exact type (location of collection and pre-treatment) of the clay mineral. We suggest that apparently contradictory results obtained by different groups with different setups are indeed in good agreement when only clay minerals of the same type and amount per droplet are compared. The natural sample from the Hoggar Mountains, a region whose dusts have been shown to be composed mainly of illite, showed very similar freezing characteristics (standard and best) to the illites. Relating the concentration of best IN to the dust concentration in the atmosphere suggested that the best IN in the Hoggar sample would be common enough downwind of their source region to account for ambient IN number densities in the temperature range of 250-260 K at least during dust events.

show abstract

Characterization of African dust over southern Italy

Cited by 86 publications

References 42 publications

PM<sub>1</sub> geochemical and mineralogical characterization using SEM-EDX to identify particle origin – Agri Valley pilot area (Basilicata, southern Italy)

PM<sub>1</sub> geochemical and mineralogical characterization using SEM-EDX to identify particle origin – Agri Valley pilot area (Basilicata, southern Italy)

Long-range transport of giant particles in Asian dust identified by physical, mineralogical, and meteorological analysis

Ice nucleation efficiency of clay minerals in the immersion mode

Contact Info

Product

Resources

About

Characterization of African dust over southern Italy

Cited by 86 publications

References 42 publications

PM&lt;sub&gt;1&lt;/sub&gt; geochemical and mineralogical characterization using SEM-EDX to identify particle origin – Agri Valley pilot area (Basilicata, southern Italy)

PM&lt;sub&gt;1&lt;/sub&gt; geochemical and mineralogical characterization using SEM-EDX to identify particle origin – Agri Valley pilot area (Basilicata, southern Italy)

Long-range transport of giant particles in Asian dust identified by physical, mineralogical, and meteorological analysis

Ice nucleation efficiency of clay minerals in the immersion mode

Contact Info

Product

Resources

About

PM<sub>1</sub> geochemical and mineralogical characterization using SEM-EDX to identify particle origin – Agri Valley pilot area (Basilicata, southern Italy)

PM<sub>1</sub> geochemical and mineralogical characterization using SEM-EDX to identify particle origin – Agri Valley pilot area (Basilicata, southern Italy)