This paper analyzes PM10 concentration data collected at 10 stations for the period of 2005-2009 by Air Quality Section of Istanbul Municipality. The analysis has been focused on spatial and temporal variations of the pollutants and their possible sources in the urban zones of the city. PM10 concentrations in Istanbul show significant variations across the city, with current PM10 levels at several traffic hot points and industrial zones which exceed EC air quality limit. The general temporal pattern is characterized by high concentrations in winter and low in summer. The number of exceedences allowed by the EU was surpassed at all monitoring sites during the analyzed years which reflect the serious pollution problem in the city. (C) 2011 Elsevier Ltd. All rights reserved.