African dust particles over the western Caribbean: Chemical characterization

Abstract

African dust (AD) plays a key role in atmospheric and biogeochemical processes across various ecosystems, yet its impact in Mexico, particularly in the Yucatan Peninsula (YP), remains understudied. This study chemically characterized AD transported to the YP during the massive “Godzilla” event in June 2020 and subsequent intrusions in 2021. The objective was to describe the chemical composition of dust, trace its origins, and assess its influence on atmospheric particles at three sites: Cozumel, Mérida, and Sisal. Aerosol samples were collected using PM₁₀ and PM_2.5 samplers and analyzed via Inductively Coupled Plasma-Mass Spectroscopy, X-ray fluorescence, and ion chromatography. Satellite imagery and air mass trajectories were used to identify periods with AD transport. Descriptive statistics and hierarchical clustering were used to identify intrusion periods and group samples based on their chemical compositions. Our results showed that PM₁₀ concentrations during AD events increased up to 20 times compared to baseline levels. Among the analyzed elements, Al, Fe, Ca, and Si were the most abundant. Enrichment of ionic species like SO₄²⁻ and NO₃⁻ was attributed to marine sources and local emissions. Correlation analysis and rare earth element clustering confirmed the African origin of the dust, primarily from Morocco and northern Algeria and Mali (Sahara region), with evidence of particle dilution as the dust traveled across the YP. These findings emphasize the significant role of AD intrusions in altering the aerosol chemical composition in the YP, contributing to a better understanding of dust and element transport mechanisms and their atmospheric and biogeochemical impacts in the region.