The breakdowm voliage (BDV characteristics of coiripres.seil gas -insuluted systenrs has been obtained in sulphur-hmujluoride SF6 and Air for wire conducting particlesf i e d to the center ofone electrode.The main object of thispaper is to hold comparison between the pi?t$ormances of compressed SF 6 arid Air with particle contamination. The resubs of this comparison m q make it possible to perform future experiments usingAir ruther than the more expensive and kss accessible SF6. The perfi,rinuiice of particle dimensions on the breakdown vobagejiir compressed gases systems with and without space charge effects are curried nut. The breakdown voliage-pressure characteristics for a parallel plane gap contaminated by a fiedpariiclef or SF 6 and Air while a countingfor positive ions space charge effect are presented in this puper. A coimparison between breakdown vobages for SF6 and Air gaps with and without space charge effects are uh-0 stirdied in this work.