Exploring the particle size effect, land use classification, and magnetic characteristics of street dust in urbanized areas in Poland

Street dust was collected from 149 locations ("all") and fractionated into five size-dependent categories: (1-0.8 mm) "0.8," (0.8-0.6 mm) "0.6," (0.6-0.4 mm) "0.4," (0.4-0.2 mm) "0.2," and (< 0.2 mm) " < 0.2." The main aims were to investigate the role of grain size in differentiating magnetic properties and identify land use factors affecting the magnetic and grain size distribution of street dust. The mass-specific magnetic susceptibility (χ) for "all" exhibited spatial variability, ranging from 30 to 545 × 10⁸ m³/kg. The average χ for " < 0.2" was 68% higher in Area 1 and 195% higher in Areas 2&3 compared to the "all" samples. The 0.4-0.2 mm grain fraction was the most abundant and comprising 40% ± 7% of the samples in Area 1, 38% ± 9% in Area 2, and 39% ± 12% in Area 3. Area 1 "all" samples predominantly consisted of particles around 1 μm, while samples from Areas 2&3 featured grains ranging between 1 and 5 μm. This study is important as it provides new insights into how grain size and land use factors interact to affect the magnetic properties of street dust, which can be used as an effective indicator for monitoring urban pollution.