To　mitigate　the　damage　caused　by　methane　explosions,　this　paper　conducts　experiments　on　methane　explosion　suppression　by　CO2　and　air　(for　comparison)-driven　NaHCO3　powder　using　a　1　m3　spherical　explosion　test　system.　The　results　indicate　that　the　explosion　suppression　effect　was　gradually　enhanced　with　the　increase　of　NaHCO3　powder　concentration.　Driven　by　air,　as　the　concentration　of　NaHCO3　powder　increases,　the　flame　becomes　darker　and　the　propagation　speed　slows　down.　After　adding　700　g/m3　NaHCO3　powder,　methane　cannot　be　ignited.　The　significant　concentration　range　for　explosion　suppression　efficiency　is　between　200　g/m3　and　500　g/m3.　Driven　by　CO2,　the　flame　evolves　more　slowly,　the　flame　shape　is　more　irregular,　and　the　flame　brightness　is　lower.　Compared　with　air　propulsion,　the　required　NaHCO3　powder　for　complete　explosion　suppression　is　reduced　by　100　g/m3,　and　the　required　NaHCO3　for　related　explosion　suppression　effects　is　reduced　by　100　g/m3.　The　explosion　suppression　effect　of　CO2　driven　NaHCO3　powder　is　superior　to　the　sum　of　the　suppression　effects　of　high-pressure　CO2　gas　injection　and　air　driven　NaHCO3　powder.　The　explosion　suppression　effect　of　CO2　enables　NaHCO3　powder　to　fully　decompose　and　exert　the　best　inhibitory　effect;　The　CO2　generated　by　the　decomposition　of　NaHCO3　can　further　enhance　the　suppression　effect　of　CO2,　and　the　two　can　thus　produce　a　synergistic　inhibitory　effect.　©　2025　Elsevier　Ltd