Airborne particles can be removed by air ions in enclosed environment, but the main drawback of this method is the formation of harmful by-products such as ozone (O3). In this study, we use ambient air and inert gas, including argon (Ar) and Nitrogen (N2) to generate negative ions respectively, and then release those ions into an enclosed chamber with ambient air. We then investigated the particle concentration decay rates and O3 concentration increase in the chamber. We found that the particle concentration decay rates were 0.343 min-1, 0.209 min-1 and 0.274 min-1 when ions were generated in ambient air, Ar and N2 respectively. The ozone concentration does not show a marked increase when using either ambient air or inert gas (Ar and N2) to generate ions. Since the temperature and humidity of ambient air may influence the ozone generation during ionizing, further study should be investigated.