ORIGINAL PAPER Concentration, sources and human health risk of heavy metals and polycyclic aromatic hydrocarbons bound PM 2.5 ambient air, Tehran, Iran Saeed Motesaddi Zarandi . Abbas Shahsavani . Fariba Khodagholi . Yadolah Fakhri Received: 12 July 2018 / Accepted: 4 December 2018 Ó Springer Nature B.V. 2018 Abstract The exposure to heavy metals and poly- cyclic aromatic hydrocarbons (PAHs) bound to par- ticulate matter 2.5 (PM 2.5 ) ambient air can result in some adverse health effect. In the current study, PM 2.5 ambient air of Tehran metropolitan, Iran, was charac- terized by the aid of scanning electron microscope and energy-dispersive X-ray techniques. Also, the human health risk of heavy metals and PAHs bound PM 2.5 for adults and children was assessed using the Monte Carlo simulation method. According to our findings, a size range of 0.97–2.46 lm with an average diameter of 1.56 lm for PM 2.5 was noted. The average concentration of PM 2.5 in ambient air (8.29E? 04 ± 2.94E?04 ng m -3 ) significantly (p \ 0.05) was suppressed the national (2.50E?04 ng m -3 ), World Health Organization (2.50E?04 ng m -3 ) and Environmental Protection Agency (3.50E? 04 ng m -3 ) standard limits. The rank order of heavy metals bound PM 2.5 was determined as Al [ Cu [ Cd [ Cr [ Pb [ Ni [ Fe [ Mn. The maximum concentration among 16 PAHs compounds investi- gated was correlated with Phenanthrene. Considering the principal component analysis, the main source of heavy metals (Ni, Pb and Cr) is vehicle combustion. Moreover, the rank order of exposure pathways based on their health risk was ingestion [ inhalation [ der- mal contact. Moreover, the significant health risks for Tehran residents due to heavy metals bound PM 2.5 [target hazard quotient [ 1; carcinogenic risk [ 1.00 E-06)] were noted based on the health risk assess- ment. Excessive carcinogenic risk (ECR) of PAHs bound PM 2.5 was 4.16E-07 that demonstrated that there is no considerable risk (ECR \ 1.00E-06). Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10653-018-0229-2) con- tains supplementary material, which is available to authorized users. S. Motesaddi Zarandi Á A. Shahsavani Department of Environmental Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran A. Shahsavani Environmental and Occupational Hazards Control Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran F. Khodagholi Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran Y. Fakhri (&) Student Research Committee, Department of Environmental Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran e-mail: Ya.fakhri@gmail.com 123 Environ Geochem Health https://doi.org/10.1007/s10653-018-0229-2