A critical eye on the destructive impact of air pollution in Tehran is needed as the basis for urban planning, protection policy and management. This paper is focused on modeling in the GIS (Geospatial Information System) to estimate the concentration of particulate matter (PM) in any point of a typical part of Tehran which extends over 18.2 km2 and includes the so-called â€œTraffic Zoneâ€. Many important general hospitals are located in this region, some of which are within the zone. The model is built on the data obtained in 42 stations located within the region. The results strongly indicate that the concentrations of PM10, PM2.5 and PM1.0 of any points inside the region, including the traffic zone, do not meet the required international standard values. The extracted estimate values for the 22 hospitals reveal that the concentration of PM10 for â€œAzadi Psychicâ€, â€œChildrenâ€ and â€œMustafa Khomeiniâ€ hospitals are the worst, estimating from the model to be 119.42 Î¼g/m3, 107.09 Î¼g/m3 and 101.14 Î¼g/m3 respectively. The percent ratio of the mean concentrations of PM10 /PM2.5 / PM1.0 in this region is found to be approximately 7: 2: 1.