[Scenario Simulation Study Constrained by the Ambient Air Quality Standards in Nanjing]

With the constraint that all six major pollutants in Nanjing must meet the air quality standards by 2030, on the basis of the 2015 emission inventory, the CMAQ air quality model was used to conduct PM_2.5 sensitivity tests, and scenario analysis was used to predict the emission inventory and the air quality of four emission reduction scenarios were simulated. Finally, the total control index under the constraint of meeting the standards was obtained. The results show that primary particulate matter (PPM) reduction is the most effective at reducing the concentration of PM_2.5 in the atmosphere, on the basis of emission reduction in surrounding areas, PPM emission reduction accounts for 88% of the total reduction of the annual average concentration of PM_2.5, followed by NH₃, NO, SO₂, and VOCs, which contribute to 10.3%, 5.5%, 3.2%, and 0.5%, respectively. Compared to 2015, the reduction ratios of the major pollutants are between 22% and 53%. Controlling the activity level is more effective for SO₂, NH₃ and CO emissions reduction, while there is still more opportunity for NO and VOCs end treatment. When the emissions of SO₂, NO, PM₁₀, PM_2.5, BC, OC, CO, VOCs, and NH₃ are controlled to 2.43×10⁴, 8.47×10⁴, 9.42×10⁴, 3.74×10⁴, 0.19×10⁴, 0.30×10⁴, 26.56×10⁴, 13.08×10⁴, and 1.50×10⁴ t, respectively, it is expected that the levels of the six pollutants in Nanjing can meet the national ambient air quality level 2 standards.