Exposure levels and health risk of PAHs associated with fine and ultrafine aerosols in an urban site in northern Algeria

Size distribution of toxicants in airborne particulates remains insufficiently investigated in Algeria. A 1-year campaign was performed at Bab Ezzouar, Algiers (Algeria), aimed at characterizing particulates for their physical and chemical features. For this purpose, scanning electronic microscopy (SEM), Raman spectroscopy (RaS), and GC-MS methodologies were applied. The samples were collected on daily basis by means of a high-volume sampling (HVS) system equipped with cascade impactor separating three size fractions, i.e., particles with aerodynamic diameters d < 1.0 μm (PM1), 1.0 μm <2.5 μm (PM2.5), and 2.5 μm <10 μm (PM10), respectively. The organic fraction was recovered from substrate through solvent extraction in an ultrasonic bath, separated and purified by column chromatography, then analyzed by gas chromatography coupled with mass spectrometry (GC-MS). Investigation was focused on polycyclic aromatic hydrocarbons (PAHs) and the concentration ratios suitable to investigate the source nature. Further information was drawn from SEM and Raman analyses. Total PAH concentrations ranged broadly throughout the study period (namely, from 4.1 to 59.7 ng m-3 for PM1, from 2.72 to 32.3 ngm-3 for PM2.5 and from3.30 to 32.7 ngm-3 for PM10). Both approaches and principal component analysis (PCA) of data revealed that emission from vehicles was the most important PAH source, while tobacco smoke provided an additional contribution.