Particle Size Variation in Diesel Car Exhaust

The Electrical Aerosol Analyzer (EAA) has been used to measure the particle size-distribution of the exhaust aerosol produced by five diesel cars under a variety of steady-state operating conditions. A good correlation was found between simultaneous EAA and filter determinations of mass emission rate for these cars. For the entire range of cars, speeds, and loads tested, the mass median diameter was about 0.1 pm, with a range from 0.05 pm to 0.22 pm. There was no consistent effect of speed on particle size in this group of cars, but there was a slight tendency toward larger particle sizes as the load increased.