This study analyzes the potential to reduce air pollutants while achieving the 2 degrees C global temperature change limit target above pre-industrial levels, by using the bottom-up optimization model, AIM/Enduse[Global]. This study focuses on; 1) estimating mitigation potentials and costs for achieving 2 degrees C, 2.5 degrees C, and 3 degrees C target scenarios, 2) assessing co-benefits of reducing air pollutants such as NOx, SO2, BC, PM, and 3) analyzing features of sectoral attributions in Annex I and Non-Annex I groups of countries. The carbon tax scenario at 50 US$/tCO2-eq in 2050 can reduce GHG emissions more than the 3 degrees C target scenario, but a higher carbon price around 400 US$/tCO2-eq in 2050 is required to achieve the 2 degrees C target scenario. However, there is also a co-benefit of large reduction potential of air pollutants, in the range of 60-80% reductions in 2050 from the reference scenario while achieving the 2 degrees C target.