Instability of emery oil particle for 10 nm engine exhaust CPC calibration

This research examined CPC calibration error due to the instability of 10 nm particle. Tandem DMA set-up was used to measure the actual particle size. Emery oil particle shrinks by 0.3 nm after classifier. Residence time in the downstream also affects the shrinkage with its rate 0.18 nm per second. In addition, we confirmed 7 nm particle shrinks more, as anticipated on Kelvin equation. Due to this shrinkage, CPC detection efficiency of 10 nm was reduced by 3% approximately.