Time-Resolved Measurements of Exhaust PM for FTP-75:Comparison of LII, ELPI, and TEOM Techniques

A direct comparison is made of time-resolved measurements of diesel PM emissions obtained using laser-induced incandescence (LII), an electrical low pressure impactor (ELPI), and a tapered element oscillating microbalance (TEOM). The measurements were made on two diesel passenger vehicles, one of which was equipped with a diesel particulate filter. Both LII and the ELPI performed well for both vehicles, whereas the TEOM lacked the sensitivity required for the filtered vehicle. We estimate that the LII system used has a limit of detection better than 0.2 mg/mi.