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, < 5-10 mu m) and fluoroapatite-like (Ca-5(PO4)(3)F, < 10-30 mu m) 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 mg kg(-1) in topsoil and from 20.1 to 75.5 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 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 similar to 600 and similar to 6300 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. [GRAPHICS]