Microstructure and chemical composition of deposited particulate matter from gasoline and diesel vehicle exhaust emissions

Abstract

A comprehensive physicochemical characterization of transport-emitted aerosols containing in vehicle exhaust emissions derived from the combustion of fuels such as diesel, premium gasoline, and unleaded gasoline was performed in this study by employing a range of analytical techniques (Laser granulometry, X-ray Fluorescence (XRF), Fourier Transform Infrared (FTIR), X-ray diffraction (DRX), Scanning Electron Microscopy (SEM), and Thermogravimetry). The X-ray diffractogram of diesel (D) derived aerosols showed an amorphous structure while those of unleaded gasoline (UG) and premium gasoline (PG), showed amorphous crystalline phases. The chemical composition of D, PG and UG derived particles was dominated by aliphatic C-H groups of alkanes with relatively low C=O groups of carboxylic acids, ketones, aldehydes, esters, lactones, and sulphate (SO4 2-) inorganic salts. The nitrogen-containing functionality (NO3-) was specific to particles of PG and UG. Laser particle size analysis showed fine particle sizes (Range) generated from diesel exhausts, thus making them dangerous when inhaled, as they can penetrate deeply into the human airways and become incorporated into the blood stream damaging other viscera.