Influence of localized sources and meteorological conditions on dry-deposited particles: A case study of Gabès, Tunisia

This study investigates the spatial and temporal variations of dry-deposited particles on the surface (by turbulence or gravity) in various sites within Gabès city and its surroundings, South-eastern Tunisia. Monthly samples were collected from five distinct locations: suburban-industrial (S2), suburban-residential (S3), and urban sites (S1, S4, and S5). The average monthly particle deposition flows ranged from 7.35 ± 4.24 g/m² to 14.41 ± 6.09 g/m², with the suburban-industrial site (S2) exhibiting the highest deposition rates. They are lower than the reference value of 30 g/m² in the AFNOR NF-X43-007, but much higher than the Swiss OPair standard (6 g/m²). Compared to the German standard (TALUFT; 10.5 g/m²), only S2 showed significant exceedances. Hierarchical cluster analysis revealed notable statistical affinities among the study sites. Heavy metal analysis indicated fluctuating concentrations across sites, with Zn being the most abundant, followed by Pb, Cu, Ni, and Cd. The enrichment factor (EF) and geoaccumulation index (Igeo) suggested varying degrees of contamination and pollution, highlighting the impact of anthropogenic sources. The findings underscore the need for targeted mitigation strategies to address particle deposition and heavy metal contamination in Gabès and similar regions globally.