Two stage aerosol samples (PM10-2.5 and PM2.5) were collected at a rural site (Erdemli) located on the coast of the Northeastern Mediterranean, between April 2001 and April 2002. A total of 581 aerosol samples were analysed for trace elements (Fe, Ti, Mn, Ca, V, Ni, Zn, Cr) and water soluble ions (Na+, NH4+, K+, Mg2+, Ca2+, Cl-, Br-, NO3-, SO42-, C2O42- and MS-). The annual mean PM10 and PM2.5 levels were 36.4 +/- 27.8 mu g m(-3) and 9.7 +/- 5.9, respectively. The highest levels of PM10 were observed during the transition period (March, April and May) due to mineral dust transported from North Africa and during winter due to sea spray generation. However, PM2.5 levels exhibited higher concentrations during summer resulting from an enhanced production of secondary aerosols. PM10, crustal elements, sea salt aerosols and NO3- were mainly associated with the coarse mode whereas nssSO(4)(2-), C2O42-, MS-, NH4+, Cr and Ni were found predominantly in the fine fraction. Ionic balance analysis performed in the coarse and fine aerosol fractions indicated anion and cation deficiency due to CO32- and H+, respectively. A relationship between nssSO(4)(2-) and NH4+ denoted that sulphate particles were partially neutralized (70%) by ammonium. Excess-K/BC presented two distinct ratios for winter and summer, indicating two different sources: Fossil fuel burning in winter and biomass burning in summer.