Article describes and compares the sensitivity and dynamics of two fast measurement techniques for transient particulate matter (PM) emission from diesel engine. The laser induced incandescence was used as a laser based method, together with differential mobility spectrometer for rapid soot characterization. The main task is to reveal the most accurate and fast device for transient emissions. The obtained results will allow better understanding of PM formation and support dynamic emission modelling as well as control design of combustion process.