In this study, the authors have presented a numeric model (NM) for application to naphthalene (C10H8) conversion via ionization reaction in a microwave air plasma torch. The NM has included a pressure-independent enhanced electron energy distribution function (EEDF) and cross-section calculation, enhanced by a new formula of phase shift determination. Based on the validated NM, electron density n(e) and O-2(+), O-, C10H8, N-2, and O-2 particles densities were calculated, as well as the conversion rate of C10H8 molecules was predicted. The predicted results showed that the ionization impact on C10H8 molecules conversion has not exceeded 0.81 x 10(-10)%. Based on the calculated collision cross-section of each species (O-2, N-2, and C10H8) of carrier gas, the authors suggested using cubic polynomial approximations of the cross-section curves with R-Square (COD) parameter R-2 = 99%. MW power increasing in the range 1.75-20 kW has raised the electron density in the range (0.5-4.5) x 10(12) m(-3). The maximal effect of electron density decreasing with pressure increasing was simulated at values of MW power greater than 7.5 kW. Herewith, pressure increasing and MW power increasing have not had any significant effect on the average electron energy.