Particle Number and Opacity Measurements

Since Diesel Particulate Filters (DPF) have been introduced, emitted particulate mass (PM) being so small and so reduced, that the up to now measurement method, the opacity, is not adequate anymore. FOEN (Swiss Federal Office for the Environment) in collaboration with METAS (Swiss Federal Institute of Metrology) and other partners, have designed device specifications and a test procedure to measure particulate number per cubic centimeter of exhaust.
The aim of the AFHB mandate was to collect and evaluate data from construction machinery in the field. Evaluations should, among others, inform about the impact of switching from the opacimeter to the PN measurement on the fail rate during the periodic inspection.

Report B485:
Field Particle Number and Opacity Measurements on Construction Machinery