Istanbul, the biggest city of Turkey, is in a common route for air parcels. Air pollutants are carried over the city from Asian, African, and European continents. Sahara Desert, the largest dust source on earth, affects Turkey's air qualities substantially due to millions of tons of mineral dust being transported from the African continent towards Turkey every year. Although the effect of Saharan dust transportation on PM(10)concentrations in Turkey was examined many times, its effect on PM(2.5)concentrations has not been studied yet sufficiently. In February 2015, Istanbul experienced a Saharan dust episode and during this event the concentrations of particulate matter rose to very high levels. This study focuses on particulate matter concentrations (PM(10)and PM2.5) during this Saharan dust episode to better understand the effect of dust transportation on Istanbul's air quality. HYSPLIT trajectory model, satellite products, and air quality monitoring data from ground observations were utilized. We show that the PM(10)concentrations increased significantly during the dust episode while PM(2.5)concentrations didn't increase considerably. There was only a slight rise in the values of PM2.5. The significant increase for the PM(10)values can be explained by the higher gravitational settling velocities of coarse particles in the atmosphere.