Hydroxy–PAH levels in atmospheric PM10 aerosol samples correlated with season, physical factors and chemical indicators of pollution

This study describes a simple, sensitive method to determine the hydroxy–PAHs, 1–hydroxypyrene (1–OHPYR) and 2–hydroxyphenantrene (2–OHPH), along with the optimization and successful application of the procedure to the analysis of atmospheric aerosol samples. PM10 airborne particles were collected on Whatman glass fiber filters and then ultrasonically extracted into methanol. The extracts were filtered and the solvent evaporated under nitrogen flow. The resulting residues were resuspended in 1.0 mL of methanol and directly injected into an HPLC–fluorescence detection system (HPLC–FD) applying the optimal experimental conditions predicted by the optimization procedure. Clean–up of the extracts was not necessary. Using this method, hydroxy–PAHs detected at pg m−3 levels in urban aerosol samples obtained over a full year were characterized and the effects of physical (temperature, atmospheric pressure, relative humidity and solar radiation) and chemical factors (O3, NO, NO2, N2Ox and SO2) were also evaluated. Results indicate an impact of season, with highest concentrations detected in winter (October to February) and lowest in summer (May to September). Through multivariate analysis (factor and cluster analysis) correlations were identified between the levels of these compounds and several indicators of atmospheric pollution.