and secondary combustion gases occurs and this mixture is then introduced into the catalyst it has been found that due to the fact that the invention produces a catalytic operating temperature which is often in the range of 1000 u00b0 to 1800 u00b0 f some heat energy is transferred by radiation to the chamber where the ring is located this occasionally produces 34 precombustion 34 in this chamber at high burn rates the high catalytic converter heat is thus transferred to the ring chamber the ring and ring fins and also to the baffled holder or bottom plate thereby further heating the incoming gases and air it should be noted that it may be desirable to provide for variably controlling the amount of secondary air that is introduced through the ring i e fine tuning the apparatus this can be accomplished by means of a damper or with a flap in the secondary air supply channel this modification has been illustrated in a specific position but it may be placed at most any convenient location in the secondary air supply path thus it can be seen that the invention comprises not only an apparatus but a method by which particulate and combustible gas removal can be accomplished the combination of a finned holder in which the fins are preferably extended downwardly at an angle of between 40 u00b0 50 u00b0 a secondary air introduction member having graduated apertures to evenly distribute preheated secondary air and a conventional catalyst can be utilized to effect substantially better results than have been achieved by prior art apparatus and systems it should also be realized that although in the preferred embodiment the lower edge 82 of the holder is secured to the.