Hongjian Weng

Seven scenarios were designed to study the national environmental benefits of ULE in coal-fired power plants (CPPs), ULE in industrial coal burning (ICB) and NH₃ emission reduction by using the GEOS-Chem model. The results showed that although the CPPs have achieved the ULE transformation target, the PM_2.5 concentration across the country has decreased by 4.8% (1.4 μg/m³). Due to the complex non-linear chemical competition mechanism among nitrate and sulfate, the average concentration of nitrate in the country has increased by 1.5% (0.1 μg/m³), which has reduced the environmental benefits of the power plant emission reduction. If the ULE technology is applied to the ICB to further reduce NO_x and SO₂, although the PM_2.5 concentration can be reduced by 10.1% (2.9 μg/m³), the concentration of nitrate will increase by 2.7% (0.2 μg/m³). Based on the CPPs-ULE, NH₃ emissions reduced by 30% and 50% can significantly reduce the concentration of ammonium and nitrate, so that the PM_2.5 concentration is decreased by 11.5% (3.3 μg/m³) and 16.5% (4.7 μg/m³). Similarly, based on the CPPs-ICB-ULE, NH₃ emissions can be reduced by 30% and 50% and the PM_2.5 concentration reduced by 15.6% (4.4 μg/m³) and 20.3% (5.8 μg/m³). The CPPs and ICB use the ULE technology to reduce NO_x and SO₂, thereby reducing the concentration of ammonium and sulfate, causing the PM_2.5 concentration to decline, and NH₃ reduction is mainly achieved through reducing the concentration of ammonium and nitrate to reduce the concentration of PM_2.5. In order to better reduce the concentration of PM_2.5, NO_x, SO₂ and NH₃ emission reduction control measures should be comprehensively considered in different regions of China. By comprehensively considering the economic cost and environmental benefits of ULE in ICB and NH₃ emission reduction, an optimal haze control scheme can be determined.