| This work characterized burn-off emissions from automobiles. After an exhaustive literature review, engine temperatures were determined to reach a maximum temperature of approximately 110°C, while exhaust system components reached a maximum temperature around 600°C. Metal-drawing fluids were used to bend the exhaust system components during manufacturing. Because these components were not rinsed prior to incorporation into a vehicle, residues could be left on the surfaces. An experimental test chamber was constructed to conduct controlled testing of three metalworking fluids of various types to mimic real-world conditions. Real-time particle number measurements were made using a condensation particle counter and an optical particle counter. The temperature at which burn-off begins to occur was found to be around 120 to 150°C. This burn-off was found to be an evaporation-condensation phenomenon when metalworking fluid residues vaporize and condense forming fine (0.1mum to 2.5mum) and ultrafine (<0.1mum) aerosols. The temperature dependency of this phenomenon was observed to follow the Clausius-Clapeyron equation that states as temperature increases, vapor pressure increases. Most aerosol particles were observed to be in the range of less than 0.01mum to approximately 2.0mum. |
