Effectiveness of SO₂ emission control policy on power plants in the Yangtze River Delta, China—post-assessment of the 11th Five-Year Plan

Facing the air pollution problems in China, emission control strategies have been implemented within the framework of national Five-Year Plan (FYP). According to the lack of post-assessment studies in the literature, this study assessed the effectiveness of the SO₂ emission control policies on power plants after the 11th FYP (2006–2010) by modeling emission control scenarios. The idealized emission control policy (the PS90 scenario with assumption of 90% SO₂ emission reduction from power plants) could reduce the SO₂ and SO₄ ²⁻ concentrations by about 51 and 14%, respectively, over the Yangtze River Delta region. While the actual emission control condition (the P2010 scenario based on the actual emissions from power plants in 2010) demonstrated that the actual reduction benefits were 30% of SO₂ and 9% of SO₄ ²⁻. On the city scale, the P2010 scenario imposed positive benefits on Shanghai, Nanjing, Nantong, and Hangzhou with SO₂ reductions of about 55, 12, 30, and 21%, respectively, while an 11% increase of SO₂ concentration was found in Ningbo. The number of days exceeding China’s National Ambient Air Quality Standard of Class I daily SO₂ concentration was estimated to be 75, 52, 7, 77, and 40 days for Shanghai, Nanjing, Nantong, Ningbo, and Hangzhou under the real SO₂ control condition (P2010). The numbers could be decreased by 16, 11, 2, 21, and 11% if the control effect reaches the level of the PS90 scenario. This study serves as a scientific basis to design capable enforcement of emission control strategies in China in the future national plans.