Abstract
Assessing the composition and origin of atmospheric particles is crucial, as their environmental impacts are directly influenced by their physicochemical properties. This study proposes a new selective sequential extraction (SSE) protocol, designed to investigate the reactivity of aerosol particles and to serve as a preparatory step for measuring Sr–Nd–Pb isotopic signatures in dust, three well-recognized tracers of dust sources. Although sequential extraction methods are increasingly used, their performance when applied to complex, real-world aerosol mixtures remain insufficiently constrained. To this end, the SSE procedure was applied to a series of reference materials (rocks, sediments), pure phases (ash, carbonates), and tested on aerosols collected during a dust event.
Our results demonstrate that the protocol effectively separates and characterizes each aerosol fraction while preserving the silicate matrix of dust, with overall mass recoveries exceeding 72%. The water-soluble fraction accounts for up to ∼41% of total particle mass, containing sea salts and highly soluble elements from ash particles. The acid-soluble fraction comprises up to ∼18% of the mass, including anthropogenic particles, carbonates, and solubilized elements from more refractory ash particles. Such conclusions will be diagnostic for studies focusing on aerosol samples, as they aim to mimic environmentally relevant processes. By quantifying and interpreting elemental release during chemical leaching, this study provides clear insights into aerosol composition and associated element solubility.
The second key objective is to assess the robustness of Sr–Nd–Pb isotopic proxies in fingerprinting dust sources. Specifically designed to minimize analytical biases and to establish specific rules for adherence, our protocol consistently preserves the initial Sr–Nd–Pb radiogenic isotopic signatures from sources in the dust record.
•A strict protocol of chemical extraction has been designed to study the fate of aerosol (including dust).•Elemental fate observed during the protocol can be transposed to the atmospheric processes effect.•After extraction, Sr-Nd-Pb isotopes can accurately fingerprint dust sources.•Application of the protocol is encouraged in the atmospheric community studying dust transport.