To reduce the concentration of tropospheric O3, the mitigation of O3 precursors should be considered. Methane, one of the O3 precursors, is also an important GHG, and the reduction of CH4 emissions would provide both global warming mitigation and environmental protection. The influence of reducing other O3 precursor emissions on the climate is not as clear. The indirect effect of reducing BC emissions requires further studies, but the mitigation of other aerosols will lead to an increase in the global average surface temperature.