METHOD AND APPARATUS FOR MEASURING AN ELEMENTAL CARBON CONTENT IN AN AEROSOL OF SOOT PARTICLES

摘要

The invention relates to a method and apparatus for measuring an elemental carbon content in an aerosol of soot particles by exposing the particles to ultraviolet radiation to induce photoelectron emission of the particles, wherein whilst the particles receive ultraviolet radiation the aero sol with the particles is heated to an elevated temperature to remove components affecting said photoemission by the par ticles, and that a sensor is used providing a first signal which is indicative of the level of said photo emission wherein the aerosol comprising the particles is heated to a temperature higher than 180 °C. In order to apply said method and apparatus to selectively measure the elemental carbon content of specific sources like passing cars, a second sig nal produced by a CO<SUB>2</SUB> sensor. By applying a fitting function, the first and the second signal are matched, and the remain ing difference is used as a criterion to judge the quality of the measurement, allowing to discriminate between true (ac cepted) and false (unaccepted) measurements.