The Modeling Study about Impacts of Emission Control Policies for Chinese 14th Five-Year Plan on PM 2.5 and O 3 in Yangtze River Delta, China.

The Chinese government has made great efforts to combat air pollution through the reductions in SO₂, NOx and VOCs emissions, as part of its socioeconomic Five-Year Plans (FYPs). China aims to further reduce the emissions of VOCs and NOx by 10% in its upcoming 14th FYP (2021–2025). Here, we used a regional chemical transport model (e.g., WRF/CMAQ) to examine the responses of PM_2.5 and O₃ to emission control policies of the 14th FYP in the Yangtze River Delta (YRD) region. The simulation results under the 4 emission control scenarios in the 2 winter months in 2025 indicate that the average concentrations of city mean PM_2.5 in 41 cities in the YRD were predicted to only decrease by 10% under both S1 and S1_E scenarios, whereas the enhanced emission control scenarios (i.e., S2_E and S3_E) could reduce PM_2.5 in each city by more than 20%. The model simulation results for O₃ in the 3 summer months in 2025 show that the O₃ responses to the emission controls under the S1 and S1_E scenarios show different control effects on O₃ concentrations in the YRD with the increase and decrease effects, respectively. The study found that both enhanced emission control scenarios (S2_E and S3_E) could decrease O₃ in each city by more than 20% with more reductions in O₃ under the S3_E emission control scenario because of its higher control strengths for both NOx and VOCs emissions. It was found that emission reduction policies for controlling high emission sectors of NO_x and VOCs such as S2_E and S3_E were more effective for decreasing both PM_2.5 and O₃ in the YRD. This study shows that O₃ controls will benefit from well-designed air pollution control strategies for reasonable control ratios of NOx and VOCs emissions. [ABSTRACT FROM AUTHOR]