Abstract：Setting scientific acid deposition control targets was necessary to control regional acid deposition pollution. A method to set such control targets by analyzing soil acidity at selected sites under different acid deposition scenarios in the target years, combining the VSD model and cumulative frequency distribution analysis, was proposed in this study. This method was applied to the Guangzhou-Dongguan-Huizhou region. The soil acidity in 25 sites was measured and simulated by using VSD model under different acid deposition scenario, and the results were described by using cumulative frequency distribution curve. The S deposition target under different scenarios was given in the results. If S deposition was controlled solely, the short-term and long-term S deposition control targets should be 7.68~12g/(m2×a) and 10.24~16g/(m2×a), respectively, to guarantee that 80% of the ecosystem was protected, and the short-term and long-term S deposition control targets should be 5.12~8g/(m2×a) and 7.68~12g/(m2×a) respectively, to guarantee that 95% of the ecosystem was protected. If S and BC deposition were controlled simultaneously, when BC deposition was 6.4~12.8g/(m2×a), the short-term and long-term S deposition control targets should be 2.56~4g/(m2×a) and 5.12~8g/(m2×a), respectively, when BC deposition was 4.8~9.6g/(m2×a), the S deposition control target should be 2.56~4g/(m2×a), to guarantee that 80% of the ecosystem was protected; when BC deposition was 6.4~12.8g/(m2×a), the short-term and long-term S deposition control targets should be 0.64~1g/(m2×a) and 5.12~8g/(m2×a), when BC deposition was 4.8~9.6g/(m2×a), the short-term and long-term S deposition control targets should be 0.64~1g/(m2×a) and 2.56~4g/(m2×a), to guarantee that 95% of the ecosystem was protected. When BC deposition was reduced to 2~4g/(m2×a), S deposition should be controlled to 0.64~1g/(m2×a) to make sure that 80% and 95% of ecosystem was protected. Restoration measures should be taken at the same time.
