The thermal mass loss, gaseous-phase reactions, and reaction-kinetics, of five representative components of combustible solid wastes (CSWs), i.e., rice straw (RS), eucalyptus wood, blank printing paper (BPP), high-density polyethylene, and polyvinyl chloride (PVC), under argon (Ar) and carbon dioxide (CO2) atmospheres-were studied by thermogravimetric mass spectrometry toobserve the effect of CO, on the thermal degradation process The CO2 atmosphere had a bigger influence than the Ar atmosphere on the thermal mass loss of CSW; CO, affected the main gaseous product distribution, which was attributed to the-complex gas reforming reaction that occurred in the, gaseous-phase, arid:abundant CO2 promoted the formation of CO and CH4:-Whentheteinperatute was over 650 degrees C, the CO2 reduction reaction occurred in the solidphase and the residue of RS and BPP was mainly silicon, calcium, and potassium oxidizers. The best fitting mechanism of the first main mass loss stage of CSW in an Ar atmosphere was mainly the nucleation and growth model. The best fitting mechanism of the second main mass loss of biomass-based combustible solid wastes under a CO2 atmosphere was the diffuion model, anclthat- of plastic combustible solid wastes was, the reaction order model. Furthermore, dehydrochlorination of PVC occurred at 200-384 C,, wherein chlorine atoms were released iii different compound forms under Ar and CO2 atmospheres: Therefore, the emissions from the heat treatment of CSW under a CO2 atmosphere presented an improved environinental profile tompaied to those released from pyrolysis under an Ar atmosphere.