<p>There is scant information about the role of urban fluorine-bearing dust particles on the environment and public health. Bioaccesible tests, spatial distribution, and Monte Carlo-based simulations were used to determine potential health risks for fluorine concentrations in topsoil and tree dust particles in semiarid endemic Durango City, Mexico. The occurrence of fluorite-like (CaF₂, &lt; 5–10&#xa0;μm) and fluoroapatite-like (Ca₅(PO₄)₃F, &lt; 10–30&#xa0;μm) grain free particles were determined in fine topsoil and tree dust particles using Scanning Electron Microscopy (SEM–EDS). The fluorine concentrations ranged from 14.7 to 1475&#xa0;mg kg⁻¹ in topsoil and from 20.1 to 75.5&#xa0;mg kg⁻¹ in tree dust particles. Spatial distribution maps were made for these concentrations using ArcGIS to visualize urban distribution of fluorine. The Solubility Bioaccessibility Research Consortium Method (SBRC) was used to calculate the potential health risks due to accidental oral ingestion of these concentrations. Fluorine bioaccessible concentrations ranged from 59 (13 %) to 265 (38 %) mg kg⁻¹ and from 5.9 (18 %) to 69.2 (86 %) mg kg⁻¹ for topsoil and tree dust samples, respectively. A combined tree dust particles and topsoil risk analysis was conducted using Monte Carlo-based simulations. The findings revealed that for a typical intake dose of 200 and 100&#xa0;mg day⁻¹, there were no health risks for children and adults, respectively. However, a progressive increase in the intake dose revealed that significant health problems can occur due to exposure to tree dust and fine topsoil of ~ 600 and ~ 6300&#xa0;mg day⁻¹ for children and adults, respectively. Environmental and health risks were further discussed based on the context of this fluorine behavior in semiarid endemic sites.</p> Graphical Abstract <p>Durango City is a growing urban area adjacent to the historic mining waste of the Cerro de Mercado mining unit, which confers particles of these waste into the urban sprawl. Additionally, this City is within semiarid fluorosis endemic region. The graphical abstract was designed to illustrate fluorine behavior accounting for urban dust containing fluorine-bearing phases (e.g., fluorapatite-like and fluorite-like) with sizes ranged 1–50&#xa0;µm enabling potential oral ingestion. Fluorine concentration in topsoil under carbonated-alkaline conditions reaches 1401&#xa0;mg kg⁻¹, two orders of magnitude higher than those under acidic or neutral conditions. Monte Carlo-based simulations also predicts an increased risk to health when considering additional dose intake of these fluorine sources. The samples are powder on the leaf trees (110 samples) and topsoil (135 samples). These findings were mapped to illustrate changes of chemical stability for fluorine-bearing phases and the corresponding fluorine concentrations to highlight occurrences accounting for oral ingestion risks.</p> <p></p>