In this study an experimental investigation has been conducted to remove NOx and SO$_2$simultaneously from a combustion flue gases were consisted of NO-SO$_2$-$CO_2$-$N_2$-O$_2$([NO]o:200ppm and [SO$_2$]o:800ppm) and the injection gases used as radical source gases were NH$_3$-Ar-air and CH$_4$-Ar-air. NOx and SO$_2$removal efficiency and the other by-products were measured by Fourier Transform Infrared(FTIR) as well as SO$_2$, NOx and NO$_2$gas detectors. and SEM images after sampling. The results showed that a significant Nucleating Particle Counter(CNPC) and SEM images after sampling. The results showed that a significant aerosol particle formation was observed during a simultaneous NOx and SO$_2$removal operation in corona radical shower systems. The diameter of aerosol particles was in the range of 0.18 to 3.6${mu}{ extrm}{m}$ with a maximum fraction of particles at particles diameter of 1${mu}{ extrm}{m}$. The NOx removal efficiency significantly increased with increasing applied voltage and NH$_3$molecule ratio. The SO$_2$removal efficiency was not significantly effected by applied voltage and slightly increased with increasing NH$_3$molecule ratio. It could be found that it is possible to use CH$_4$for NOx and SO$_2$removal by corona radical shower systems.