Investigation of aerosol trace element concentrations nearby Algiers for environmental monitoring using instrumental neutron activation analysis

Abstract

The aim of this study was to enhance the use of instrumental neutron activation analysis (INAA) for long-term monitoring of air pollution and to identify critical sources of air pollution. For the collection of total suspended particulatematter (TSP), a filter unit lowvolume sampler (LVS)wasemployed. One hundred and seventeen sampleswere collected during 2010, 2011, and 2012, both onweekdays andweekends at amonitoring station located in Draria city, a suburban site near Algiers, Algeria. The concentrations of 25 trace elements (As, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Eu, Fe, Gd, Hf, K, La, Mn, Mo, Na, Sb, Sc, Se, Sm, Sr, V, and Zn) were determined by INAA using short and long neutron irradiation technique. Generally lower concentration values were observed during the weekends compared to theweekdays for almost all elements. Themean TSP concentration (34.8 μg/m3) showed a seasonal pattern with higher levels during summer. The weekday/weekend ratio of TSP was 1.3 higher during summer than in winter. The concentrations of the elements Sb, Se, and Cd are found to be highly enriched in atmospheric particulate matter. According to their high enrichment factors (EFs), it was possible to establish that these elements are of anthropogenic origin coming fromautomobile exhaustswhich is the main source of emission in this area. The typical suburban background TSP and trace element levels were compared with literature data fromother regions around theworld, andwere lower than those reported in an urban site in Algiers in a previous study. Significant correlations between elements were found (Pearson's coefficients N0.5) suggesting that the contaminant trace elements may be discharged from the same sources.