The objective of this study was to develop an efficient and sensitive analytical protocol for the determination of nitrated polycyclic aromatic hydrocarbons (NPAHs) in aerosol samples. The separation of 16 NPAH (mono-and dinitro-PAH) was achieved by reversed-phase high-performance liquid chromatography (HPLC) followed by =.28w?>on-line reduction of the NPAHs to their corresponding amino polycyclic aromatic hydrocarbons (APAHs) and quantification by fluorescence detection. The main factors affecting the on-line reduction efficiency, such as the flow rate, the temperature, the position and packing of the reduction column were evaluated and optimised. The optimal conditions obtained were: packing of the reduction column with Pt-Al₂O₃; a reduction column oven temperature of 90 °C; a flow rate of 0.8 mL min⁻¹. The resulting detection limits of the method ranged between 0.06 (2 NN) and 1.25 μg L⁻¹ (1.8 DNN), with an uncertainty of about 6%. The lifetime of the reduction column was identical to that of a typical analytical column. This analytical method was applied to particulate matter samples collected during December 2005 and August 2006 in Strasbourg (Alsace, eastern France). The NPAH concentrations observed for this urban site showed that the compounds are more abundant during winter (average of 534 pg m⁻³) than during summer (average of 118 pg m⁻³). 1-Nitropyrene was the predominant NPAH species, independent of season.