Abstract: Particulate concentration of diesel exhaust is measured by collecting the diesel particulate on a filter while measuring the amount of exhaust passing through the filter. The filtered particlate is then heated in an oxygen rich enviroment to oxidize carbon within the particulate to carbon dioxide. The amount of resulting carbon dioxide is measured to derive a corresponding measurement of the amount of filterd particulate. Particulate concentration is calculated by comparing the amount of particulate with the measured amount of exhaust passed through the filter. Filtered particulate can be heated incrementally to obtain a measurement of volatile components within the particulate prior to the oxidation of the non-volatile carbon component. The filter employed to collect the particulate is of a high temperature resistant type making it reusable and can be either integral with or inserted into the oxidation chamber of the instrument.