36. Thermographic analysis of gasoline and diesel exhaust particles

In Mexico City there are more than 4 million cars and trucks. Despite the efforts of the Mexico City government and the rigorous laws and regulations on automotive emissions, close to 1 million vehicles are circulating every day, resulting in gases and particles from gasoline and diesel motors exhaust, major pollutants in the Mexico City area. The evaluation of thermograms from Evolve Gas Analysis (EGA) is a very useful technique to estimate the carbon content of aerosols. Gasoline and diesel motors particles were collected directly from the source and separated in eight aerodynamic diameters, ranging from 10-0.18 µm with a Micro Orifice Uniform Impactor, MOUDI. The objective of the present study was to evaluate the relative amount of organic carbon (OC) and black carbon (BC) contributed by diesel and gasoline engines in Mexico City. The fraction of semi volatile organics from the gasoline exhaust particles is higher than those emitted from diesel engines and the presence of black carbon is minimum at particle size diameter above 1.00 µm. However, the total amount of particles produced by diesel vehicles is thirty times higher than gasoline vehicles.

Keywords: EGA, thermogram, diesel, gasoline, exhaust particles, MOUDI