Lead (Pb) air pollution remains a critical public health challenge, particularly for children’s neurodevelopment. While primary industrial emissions have declined, many post-industrial cities face persistent atmospheric Pb from the resuspension of legacy contamination. This study examines spatiotemporal patterns of airborne Pb, measured in Total Suspended Particle (TSP) samples, in Torreón, México—a city with decades of contamination from: (1) a major Ag-Cd-Pb-Zn smelter (operational since 1901) and (2) legacy leaded gasoline emissions (1920s-1997). Using a five-year monitoring dataset, we evaluated Pb distribution relative to smelter proximity, climate, and topography. The results revealed concerning Pb concentrations ranging from 0.005 to 4.49 µg m− 3 (median: 0.30 µg m⁻³). Notably, over 82% of 3‑month monitoring blocks across all stations around the smelter exceeded the U.S. EPA NAAQS of 0.15 µg m− 3. The data reveals dual control on exposure: seasonal meteorology drives resuspension, while topography governs spatial distribution. The winter-spring months (December-May) featured the most frequent severe pollution events, coinciding with atmospheric stagnation, thermal inversions, and dust storms (tolvaneras) that mobilize legacy Pb. Conversely, the rainy season (July-September) showed the lowest concentrations, underscoring the role of precipitation in suppressing dust. Concentrations within 2 km of the smelter were 8–15 times higher than urban background levels, and the Sierra de las Noas range acts as a topographic barrier, trapping metal-rich particles. This five-year record demonstrates that despite the phase-out of primary emissions decades ago, airborne Pb in arid Torreón is now dominantly a secondary pollutant, with its flux controlled by environmental conditions that reactivate the extensive soil/dust reservoir. Consequently, mitigating this persistent health risk requires: (1) comprehensive remediation of legacy Pb in surface soils and dust, particularly in identified hotspots; and (2) targeted biomonitoring programs of child blood Pb levels in high-exposure zones. Torreon exhibits critically high airborne-Pb levels, driven by legacy contamination. Proximity to the historical smelter is a primary determinant of spatial exposure gradients. Seasonal meteorology (inversions, dust storms) and orography (the Sierra de las Noas) control the redistribution and trapping of Pb-rich particles. The sustained airborne-Pb levels present a critical health risk in Torreón, particularly for children.
Soto-Jiménez et al. (Mon,) studied this question.