We establish the nonlinear responses between nitrate and NO_x in China. Reduction of NO_x results in linearly lower nitrate in summer–autumn whereas an increase of winter nitrate until an inflexion point at 40–50 % reduction due to the excess oxidants. NH₃ and VOCs are effective in controlling nitrate pollution, whereas decreasing the SO₂ and NO_x emissions may have counterintuitive effects on nitrate aerosols. This paper helps understand the nonlinear aerosol and photochemistry feedback.