August 1, 2023 Dataset Open Access

Quantification of mineral dust (MD) contribution to Arctic aerosol, analysis of samples collected at the Zeppelin Observatory (Metadata RADIATE TA Proposal 22002905-ST)

Chiari, Massimo; Nava, Silvia; Uggerud, Hilde Thelle; Vadset, Marit

Proposal title "Quantification of mineral dust (MD) contribution to Arctic aerosol, analysis of samples collected at the Zeppelin Observatory". Measurements carried out at the external beam set-up for atmospheric aerosol analysis of the INFN LABEC accelerator laboratory), from 7 till 7 March 2023. Hands-on mode.

Aerosols interfere with the polar energy balance directly, by absorbing or scattering radiation, and indirectly by affecting cloud formation and properties, and is a function of the aerosol physical, optical, and chemical properties. Aeolian mineral dust (MD) can be a significant contributor to the Arctic aerosol and has a warming effect by absorbing radiation, as well as it decreases the surface albedo when deposited on snow and ice and enhance smelting (of snow and ice). MD particles may also be efficient scatterers of sunlight and thus can have a cooling effect. MD in the Arctic atmosphere can both be long-range transported (LRT) and originate from intrinsic sources. Atmospheric MD concentrations is commonly estimated by analysing a selection of trace elements associated with MD, such as Silicon (Si), Aluminium (Al), Iron (Fe), Manganese (Mn), and Titanium (Ti); various element ratios can serve as fingerprints and aid in separating MD of local origin vs. LRT MD, e.g., from Eurasia

The main objective of this work is to evaluate NILU’s analytical method, used in monitoring of Arctic aerosol, for trace elements associated with Mineral Dust (Al, Fe, Mn, and Ti) by comparing it with PIXE, and hence NILU's assessment of the Arctic Mineral Dust concentration.

Ambient aerosol filters samples were collected at the Arctic Zeppelin Observatory during the years 2017-2018-2019-2020. The filter samples typically have a low loading, although Mineral Dust episodes occur. Aerosol was collected on Whatman 41 filters (150 mm diameter) with a sampling time of 48 hours, providing an air volume of 2100 m3. The particle fraction collected is PM3. 47 mm diameter punches were provided. The filters have already been analyzed for Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, and Pb, using ICP-MS.

Ambient aerosol samples collected on quartz fibre filters (one week sampling time) were also selected for periods with high aerosol concentrations and analysed for the more heavie elements (heavier than Ca).

A total of about 165 samples (about 115 on Whatman and 50 on quartz filters) were analysed by PIXE using a 3 MeV proton beam. Aerosol samples collected on quartz fibre filters were also analysed by PIGE (Particle-Induced Gamma-ray Emission) for the quantification of Al. A set of elemental standards and an aerosol reference standard (NIST 2783) were analysed as well for quality assurance purposes and to check the accuracy of quantitative results.