Enrichment factors to assess the anthropogenic influence on PM10 in Gijón (Spain)

Abstract

Thirty-two chemical species were determined in PM sampled at a suburban site on the north coast of Spain. Enrichment factors were applied to infer their soil/non-soil origin. The geochemical ratios were calculated using two databases: soil composition from locations in the surroundings of the sampling station and the Earth's average upper-crust composition. In the present study, dissimilarities were found between the enrichment factors obtained using these two databases. Al, Ti, La and Ce were taken as the reference elements to normalise the data, reaching analogous conclusions. Bi, Cd, Cu, Sb, Se, Sn and Zn were associated with predominantly non-soil apportionments. As the relevance of soil/non-soil sources for the other analysed elements was found to be variable, they were probably of mixed origin. Furthermore, pairs of elements showed strong relationships, thus pointing to a common origin. Na-Mg and Co-Ni, with Pearson correlation coefficients above 0.9, were respectively related to marine and industrial apportionments. Enrichment factors have proved to be a useful tool to distinguish the soil/non-soil origin of chemical species present in airborne particulate matter. However, the choice of the reference database for soil composition considerably determined the accuracy of the conclusions.

Chemical composition and trajectories of atmospheric particles at the Machu Picchu Peruvian Antarctic scientific station (62.09º S, 58.47º W)

“…where X is the concentration of each trace element, X/ T i air is the concentration ratio between element X and the reference T i element in the aerosol sample (PM 2.5 and PM 10 ), and X/T i crustal is the concentration ratio between the element X and the reference T i element in the soil surrounding the sampling site, given its abundance (in ppm) in the Earth's crust (Wedepohl, 1995). Calculated EF values < 5 are explained as having a crustal or soil origin (Megido et al, 2017;Marina-Montes et al, 2020); if EF > 10 it indicates an enrichment attributable to additional sources, a significant fraction of anthropogenic origin (Chester et al, 2000;Bazzano et al, 2015;Marina-Montes et al, 2020). Hierarchical cluster analysis (HCA) using Ward's method of linkage and the squared Euclidean distance for similarities was used to segregate associations within the group of trace elements to identify possible pollutant sources (Hastie et al, 2009).…”

Geochemistry of the Dust Collected by Passive Samplers as a Tool for Search of Pollution Sources: The Case of Klaipėda Port, Lithuania

“…Presently normalized enrichment factor is widely used and usually entitled "enrichment factor" without the word "normalized" and with abbreviation EF. It was used for dust studies by some researchers, e.g., [36,[40][41][42] and others. Now this index is sometimes used for dust contamination classification, e.g., [43][44][45], to distinguish five so-called contamination classes (SCC): <2-minimal; 2-5-moderate; 5-20-significant; 20-40-very high; >40-extreme.…”

“…The choice of either Cv or Bn can lead to different general formal conclusion about ambient air state. The resulting uncertainty, when the same name is used for indices based on either Cv or Bn is being addressed by a growing number of researchers such as [36,[40][41][42] and others. Therefore, we shall try to compare data classifications according to SCC in discussion, where the effectiveness of search for presumable contamination hotspots and sources will be analyzed.…”

Influence of Saharan Dust on the Composition of Urban Aerosols in Palermo City (Italy)

“…In a typical urban environment in Southern Europe, such as Barcelona, natural sources, including sea spray, biogenic emissions, and mineral dust, were found to contribute around 20% of the PM mass. In addition, the study by Kassomenos et al [43] further highlights the significance of natural and secondary particles to PM 10 levels in different European cities such as London, Athens, and Madrid [41]. Mineral dust (with a mass fraction of 13%) is one of the largest natural PM sources globally.…”

“…Soil can be considered among the major contributors to particulate matter (PM) in the atmosphere [37,41,42]. In a typical urban environment in Southern Europe, such as Barcelona, natural sources, including sea spray, biogenic emissions, and mineral dust, were found to contribute around 20% of the PM mass.…”