Abstarct: The aim of this study was to determine the concentration of heavy mextals and morphology and mineralogy of PM2.5 samples collected from air pollution monitoring station in Haft-Tir square (Central Tehran). For this purpose, PM2.5 samples were collected from this station by low-volume sampling device on Teflon filters during 5 months (May-September 2017). baxsed on the obtained results, variations in mextal concentration in all months of sampling time showed almost the same trend arranging in order of Zn>Ni>Pb>Cr>Cu>Cd. Comparing the mean concentration of mextals with international permissible limits showed that the concentration of Pb and Cr in PM2.5 samples was lower than that of recommended by the World Health Organization (WHO) while the average concentration of Cd and Ni in the samples was higher than those of USEPA recommended limit. According to non-cancerogenic health risk assessment, the risk index (HI) for both children and adults groups varied as Cd>Pb>Cr>Ni>Zn>Cu. Also, the health quotient (HQ) for all the studied mextals was found to be less than 1, indicating that non-carcinogenic effects will not pose for both age groups. The highest risk of carcinogenicity among mextals was about 5.3 ×10-4 for children and 4.9 ×10-4 for adults. baxsed on scanning electron microscopy images, PM2.5 are observed as a shapeless or irregular, rod-shaped, irregular spherical, completely spherical, sheeted, as well as as long chain aggregates or single crystals in the samples. Therefore, according to morphological characteristics, PM2.5 have both geogenic and man-made origin in the study station. baxsed on the chemical composition obtained from X-ray energy diffraction spectroscopy (EDS), C, O, Si, Al, Fe, Ca, S, F, K, Mg, Na and Cl are present in detectable concentrations in PM2.5 samples. According to the results of X-ray diffraction (XRD) analysis, clay minerals (kanite and illite), quartz and calcite were found as major minerals, gypsum and dolomite minerals were identified as minor minerals and wüstite and halite minerals were identified as rare mineral phases.