I. Casotti Rienda, T. Nunes, M. Soares, F. Amato, A. Sánchez de la Campa, A. Molinero-García, J. M. Martín-García, C. A. Alves. Air Quality, Atmosphere & Health, 2025
The thoracic fraction of atmospheric particulate matter (PM10) from road dust was collected with an on-site resuspension chamber on the pavements of the access roads to three quarries (limestone, granite and clay-sand). The PM10 dust loads on the roads at the entrances to these facilities (160–524 mg m−2) were up to 5–6 times higher than those obtained on the nearby arteries (37.6–102 mg m−2). The PM10 emission factors were much higher than the values obtained on urban roads, reaching 893–1932 mg km−1 veh−1 on the main roads and 2798–7299 mg km−1 veh−1 at the quarry entrances. Carbonaceous constituents represented PM10 mass fractions lower than 2.3%. Carbonates constituted 8.3% of the PM10 mass from the limestone quarry access road, compared to 2.3% in road dust from the granite and clay sand quarries. The elemental composition of PM10 from the limestone quarry access road was dominated by Ca and a much more moderate contribution from Al, Fe, K and Mg, while the abundances of K, Al, Ca and Fe were more balanced in dust samples from the roads to the other two quarries. Mineralogical analysis by XRD showed that road dust from the limestone quarry was dominated by rock minerals such as calcite (95–97%), while its presence in PM10 of roads in the vicinity of other quarries fell below 16%. Phyllosilicates and quartz were the dominant minerals in PM10 of the access roads to the granite and clay-sand quarries, respectively, with lower contributions from K-feldspar, plagioclase, calcite and dolomite. While total cancer risks remained below the generally accepted threshold, hazard index (HI) values exceeding the safety threshold of 1 were observed in most areas, particularly around granite and clay quarries, where children face an elevated non-carcinogenic risk. The ingestion route was identified as the primary contributor to these risks, with zirconium (Zr) being the dominant element influencing the HI.
