Calibration of the new electrical low pressure impactor (ELPI+)

A renewed Electrical Low Pressure Impactor (ELPI+) was introduced by Dekati Ltd. in late 2010. This study presents the collection efficiencies of the ELPI+ cascade impactor stages and the back-up filter as well as the charging efficiency of the corona charger in the size range of 0.01-10 μm. According to the measurements the impactor cut diameters are within ±10% to the predecessor except the upmost stage for which the difference was found to be −18%. The secondary collection of nanoparticles was found to be similar to the predecessor for stages with the largest cut diameters but higher for the stages with the smallest cut diameters. The charging efficiency is higher for the new charger compared to the old one by 54% at 20 nm particle size. This study also presents the first use of the Single Charged Aerosol Reference (SCAR) for impactor and charger calibrations.