Device for abatement of liquid, gaseous and/or solid pollutant substances of various kind, produced by various sources, which are contained in the exhaust smokes deriving from the combustion processes of pollutant substances of various kind, and in particular but not exclusively in the case of use of civil or industrial thermic plants, and the traffic of vehicles powered by explosion engines, the combustion of the pollutant substances happening into at least a combustion chamber communicating with the inlet of at least one flue and with a dedicated microwave generator (magnetron) providing correspondent waveguides connected sealingly between the microwave generator and openings, the smokes, reduced of an elevate percentage of pollutant substances of the same smokes, exit from the outlet of the flue, characterized by at least a heating module, communicating with inlet and the outlet of said flue, and comprising an outer envelope which is made of a metallic material, withstanding the high temperatures and impermeable at the microwaves, into which there is inserted and fixed, with the interposition of an insulating material as for example mineral wool, at least a lengthened internal cylindrical container made of mechanically withstanding metallic material and impermeable for microwaves, shaped with a peripheral wall joined at its end portions by lower and upper joining means constituted of materials with the same characteristics, delimiting at least an inner chamber, multi-modal or with dimensions greater than the electromagnetic wave spreading inside thereof, one or more lengthened tubes being housed and secured into said lengthened internal container, these tubes are passed through into the inner cavities thereof by the smokes, preferably circulating for natural draught, said lengthened tubes being made of acceptor material, preferably silicon carbide or zirconia, with characteristics such to reflect, to absorb, such to generate an infrared radiation and therefore an heating, and to allow the absorption of the energy flow of the microwaves that arrive on to the surface of said lengthened tubes, said lengthened tubes being externally covered for almost the whole extension thereof by an insulating material suitable to withstand to temperatures comprise preferably between -50°C and 3000°C, and with characteristics of radio-transparency to the frequencies comprised between 0,2 GHz and 5 GHz, therefore to the microwaves frequencies, and the surfaces of the lower and upper end portions of such an internal insulating material being covered by a respective plug means (35 and 36) of the same insulating material, which are secured on to the same surfaces, and are bored for permitting the passage of smokes in the interior thereof and are joined with the inlet and the outlet of said flue, respectively, said heating module being also provided with a plurality of through openings provided through the outer envelope and the vertical peripheral wall, in positions coinciding to each other, and communicating with at least the dedicated microwave generator (magnetron), through the correspondent waveguides connected sealingly between the microwave generator and the through openings, in such a way that the microwaves generated by the generator be distributed, directed and let to interfere with the material constituting the vertical tubes, by passing through said insulating materials (31, 34), said microwave generator may be regulated in such a way as to generate microwaves with a power comprised preferably between 200 W and 20000 W, which microwaves decrease of energy passing at first through internal insulating material, and then passing through said lengthened tubes generate infrared radiations that radiate into the relative internal cavity of said lengthened tubes, by determining a further heating of the circulating hot smokes, and a simultaneous multiple reflection of the microwaves into said internal cavities, in such a way that, caused by the repeated reflections of the microwave into the internal cavities and of its contact with the high temperatures, with the nonhomogeneties and the different densities of the gas contained into the circulating smokes, there are generated peaks of energy of the microwaves named hotspots into said internal cavities, that are not distributed in an orderly and homogenous manner into the same internal cavities, but are surprisingly distributed in an casual manner and in variable and different positions into the same internal cavities, in a way that, by dimensioning opportunely both the characteristics of the microwaves, that are directed into the internal cavity, and the size and the quality of the acceptor material of the tubes, the hot spots thereby generated and distributed in a casual manner into the above-said internal cavities may reach very high temperatures, also in the order of size comprised preferably but not necessary between about 1200° C and about 2600° C, that are sufficient to determine the heating of the smokes passing at these very high temperatures, and to dissociate the molecules of various compounds constituting the pollutant substances of the smokes, in order to discharge in the environment the smokes that contain an high percentage of single non-pollutant substances, by reducing considerably the pollution of the same, which smokes during the contact with the lower room temperatures may not therefore combine to each other for forming again the pollutant substances.