Rainfall components were analyzed by separating extreme ion and pH concentrations in northwestern Turkey for the first time. While major anions (SO42-, NO3-, Cl-) and cations (Na+, K+, Mg2+, Ca2+ NH4+) were evaluated using backtajectory analysis according to the highest occurrence ratios, the pH values were organized and analyzed by their minimum rates. Rainfall data were recorded at 4 selected locations in the Thrace Region of Turkey. The episodes were also categorized as concurrent precipitation days to obtain more detailed picture on the motion of the air currents. Among the stations we studied, it is found that Istanbul hold the highest peak concentrations in five of the total ten components recorded between 2000 and 2002. At each measurement location, it was found that the Ca2+ was the dominant cation based on the total episode number and average maximum concentration. In addition, as a source, southerly backtrajectories were determined. The path of the ions started over the desert region in Libya and passed through the Mediterranean Sea during the mutual episode days 5-6.4.2002.