Saharan dust impact on the chemical composition of

Authors: M R Perrone Alessandra Genga Maria Siciliano Tiziana Siciliano Fabio Paladini Pasquale Burlizzi

Publish Date: 2016/02/24

Volume: 9, Issue: 2, Pages: 127-

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Abstract

Angström exponents Å and dust concentrations from the Barcelona Supercomputing CenterDust REgional Atmospheric Model BSCDREAM were used to infer the impact of longrange transported desert dust particles at the ground level and evaluate their role on the chemical composition of PM1 and PM10 samples Å values were calculated from the scattering coefficients at 450 and 635 nm retrieved from integrating nephelometer measurements Nephelometer measurements were performed at a coastal site Lecce 4033° N 1811° E of southeastern Italy from December 2011 till November 2012 Days characterized by Å daily mean values smaller than 095 and modelled daily dust concentrations larger than 01 μg m−3 at 86 m above the ground level were considered representative of days affected by African dust particles up to the ground level dusty days Both criteria have allowed identifying 86 dusty days during the investigated period The analysis of 24h simultaneously collected PM10 and PM1 samples revealed that the PM1 mass concentrations increased linearly with PM10 both in dusty and dustfree days which were identified as the ones characterized by Å daily mean values larger than 13 and PM1/PM10 ratios larger than 035 These results suggested that the PM1 samples were also affected by desert particles on dusty days In fact chemical analyses revealed that the Al and Fe mean mass concentrations were larger in dusty day PM1 and PM10 samples Then we found that the crustal matter contribution was nearly twice and more than twice larger in dusty PM1 and PM10 samples respectively than in corresponding dustfree samples Mass contributions of organic and elemental carbon sulfates and ammonium even if smaller in dusty samples than in dustfree PM1 and PM10 samples revealed the significant role of the anthropogenic pollution also on dusty daysThis work was supported by the European Community through the ACTRIS Research Infrastructure Action under the 7th Framework Programme under ACTRIS Grant Agreement 262254 This research was supported by Project PON 254/Ric Potenziamento del “Centro Ricerche per la Salute dell’Uomo e dell’Ambiente” Cod PONa3 00334 The authors would like to acknowledge the Barcelona SuperComputing Centre for the provision of the DREAM dust profiles The authors also gratefully acknowledge the NOAA Air Resources Laboratory ARL for the provision of the HYSPLIT model used in this publication

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