Spatial Assessment of Airborne Atmospheric Heavy Metals Across Key Monitoring Stations in Baghdad

Abstract

The present study concerns the geographical assessment of atmospheric airborne heavy metals in the main monitoring stations of Baghdad during the months of May and June 2025. The heavy metals of interest are Lead (Pb), cadmium (Cd), nickel (Ni), Iron (Fe), Copper (Cu) and zinc (Zn). Air samples were collected with standardized one hour sniffer-based sampling, and the levels of heavy metals were determined in a laboratory. Geostatistical mapping and spatial interpolation were used to visualize distribution patterns and pollution hotspots across the metropolitan landscape. Results show a clear spatiotemporal variability driven by sources of legacy contamination, seasonal weather, industrial pollutants and traffic intensity. In both months, high atmospheric dispersion of river-channel airflow dynamics resulted in continually lower levels of heavy metals in the areas along the Tigris River, especially in central Al-Karkh and parts of Al-Khadimiya. However, high Zn concentrations, above 14 ppm in May, were observed near Karadaa and Al-Zafaraniya where there is a lot of traffic, construction and private generator use. Most of the metals showed higher concentrations in May (e.g., Cr: 0.84–2.31 ppm) than in June (0.231–1.16 ppm) which can be indicative of seasonal changes in air stability and emission strength. Fe showed the opposite trend, increasing from 4.05-9.91 ppm in May to 6.06-10.2 ppm in June. This increase was probably because of stronger summer winds and increased dust resuspension. Furthermore, spatial maps show much lower Fe concentrations along the Tigris corridor, supporting the moderating effect of dispersion due to river transport. The results show the combined impact of seasonal weather patterns and anthropogenic emissions on airborne metal pollution in Baghdad and highlight the urgent need for focused air quality control measures in high exposure areas