Mass concentrations, seasonal variations, chemical compositions and element sources of PM10 at an urban site in Constantine, northeast Algeria

Abstract

This study presents for the first time, the results of a one-year measurement campaign on ambient PM10 (particulate matter with aerodynamic diameter <10μm) at an urban site at Zouaghi, in the south of Constantine, Algeria. The main objective of this work was to provide PM10 mass concentrations, a chemical characterization of atmospheric particles and their seasonal variation and to identify the sources of chemical elements in the PM10. To accomplish the goal, enrichment factors (EFs), inter-element correlations, elemental ratios and principal component analysis (PCA) were used for the first time in Constantine. A total of 66 PM samples were collected during a sampling campaign which extended from January 2015 to February 2016. The PM10 samples were analyzed for a total of 48 elements by ICP-AES and ICP-MS for major elements and trace elements respectively. Enrichment factor analysis indicated that Pb, Sb, Cd, Bi, As, and Zn were mainly originated from anthropogenic sources. The ratios of Cu/Sb, Ca/Al, Zn/Pb, La/Ce and V/Ni were calculated and compared to those being reported in previous studies. A significantly higher Ca/Al ratio was dominant indicating the influence of construction dust, while a low Zn/Pb ratio was the consequence of high Pb concentrations resulting from the use of leaded gasoline. Principal component analysis allowed to identify four main groups of sources: crustal aerosol for Al, Fe, Ti, Li, Mg, Ba, Sr and rare earth elements (REEs) (47%), soil and road resuspension for Cr, As, S, P, V, Ca, Zn, Sn, Nb, K, Mg, Ba, Sr and Li (27%), traffic emission for Pb and Be (8%), and a metallurgical source for Cd and W (6%). The results of the source apportionment analysis indicate that natural dust originating from Saharan dust outbreaks (SDOs) and resuspended dust are the main sources of elements in PM10 in Constantine.