Device of modular construction which permits the simultaneous or not-simultaneous recording and characterization of solid and liquid particles and gaseous components of engine exhaust gases on various test supports, with only small or no modification of the test support. Methods are based on individual or combined usage of laser scattering techniques, laser-induced breakdown spectroscopy, laser-induced ionization spectroscopy, laser-induced atomic fluorescence spectroscopy, IR-/VIS-/UV-laser absorption spectroscopy and laser-induced incandescence. Use of individual or combined usage of such devices permits the analysis of raw exhaust gas, the conditioned and/or treated exhaust gases for monitoring and checking working pattern of engine, individual components of exhaust gas treatment and/or total system on test beds and on vehicle and can be used for control of motor and/or exhaust components, such as catalysts and particle filters, on test beds and in driven usage, e.g., in connection with, or as part of, on-board diagnostic system.