Provenance fingerprints of atmospheric dust collected at Granada city (Southern Iberian Peninsula). Evidence from quartz grains

A Molinero-García,J.M Martín-García,M.V Fernández-González,R Delgado

doi:10.1016/j.catena.2021.105738

Abstract

Dust in the Earth́s atmosphere is increasing, particularly in southern Spain. The study of dust properties allows for a hypothesis on the origin and provenance of dust. This study characterised atmospheric dust deposited in the city of Granada (south of Spain) during three spring periods (samples 4PA, 16PA, and 28PA, collected in 2012, 2013, and 2014, respectively). The aim was to ascertain dust characteristics and genesis using a set of methodological techniques. The backward trajectories study separated the samples into two groups: scarce Saharan influence (sample 16PA, 6% of backward trajectories are from, or have passed through, Africa) and greater influence (samples 4PA and 28PA, 26% and 33%, respectively). This grouping was verified by the rest of the properties analysed, namely, PM10 concentration, deposition rates, grain size, mineralogy, and elemental composition (minor, including rare earth elements). In addition, mineral quartz showed differences in particle morphology and surface microtextures. The mineralogical and geochemical studies of our samples have proved similarities with other dust collected in Granada and soils from the Iberian Peninsula. The principal component analysis of the quartz shape parameters insists on the differentiation of these groups. We propose the morphoscopy of quartz grains (a significant component of atmospheric dust) as a fingerprint of provenance.

Highlights

Atmospheric dust is one of the most abundant aerosols globally and an essential component of the Earth’s environmental system (Nickovic et al, 2012; Muhs et al, 2014; Schepanski, 2018)
African dust intrusion should be considered in the Iberian Peninsula because of the proximity of the Sahara Desert (e.g. Valenzuela et al, 2012)
par ticulate matter (PM) < 10 μm (PM10) concentration in Granada frequently exceeds both the limit value recommended by the World Health Organization (WHO) (20 μg m− 3) and the one-day limit value (50 μg m− 3) established by the European Union Directive (2008/ 50/EC) — the limits were exceeded 54 days per year− 1 in the period 2010–2020 (Junta de Andalucía, 2021a)

Summary

Introduction

Atmospheric dust is one of the most abundant aerosols globally and an essential component of the Earth’s environmental system (Nickovic et al, 2012; Muhs et al, 2014; Schepanski, 2018). The Sahara Desert is the world’s largest source of atmospheric dust (50%–70% of total emissions worldwide), contributing between 1 and 3 billion tons per year (Prospero et al, 2002; Engelbrecht et al, 2016; Huneeus et al, 2011; Russo et al, 2020). Granada city (south of the Iberian Peninsula) has one of Spain’s highest atmospheric pollution levels. PM is a major problem and an environmental risk to health that has concerned the Spanish government since it was classified as a carcinogen to humans (Group 1) (WHO, 2013a; WHO, 2018)

Methods

Results

Conclusion