Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou, 730000, China.
Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou, 730000, China; Lanzhou University Applied Technology Research Institude Co., Ltd, Lanzhou, 730000, China.
Environ Pollut. 2023 Sep 15;333:122070. doi: 10.1016/j.envpol.2023.122070. Epub 2023 Jun 16.
The accuracy of determining atmospheric chemical mechanisms is a key factor in air pollution prediction, pollution-cause analysis and the development of control schemes based on air quality model simulations. However, the reaction of NH and OH to generate NH and its subsequent reactions are often ignored in the MOZART-4 chemical mechanism. To solve this problem, the gas-phase chemical mechanism of NH was updated in this study. Response surface methodology (RSM), integrated gas-phase reaction rate (IRR) diagnosis and process analysis (PA) were used to quantify the influence of the updated NH chemical mechanism on the O simulated concentration, the nonlinear response relationship of O and its precursors, the chemical reaction rate of O generation and the meteorological transport process. The results show that the updated NH chemical mechanism can reduce the error between the simulated and observed O concentrations and better simulate the O concentration. Compared with the Base scenario (original chemical mechanism simulated), the first-order term of NH in the Updated scenario (updated NH chemical mechanism simulated) in RSM passed the significance test (p < 0.05), indicating that NH emissions have an influence on the O simulation, and the effects of the updated NH chemical mechanism on NOx-VOC-O in different cities are different. In addition, the analysis of chemical reaction rate changes showed that NH can affect the generation of O by affecting the NOx concentration and NOx circulation with radicals of OH and HO in the Updated scenario, and the change of pollutant concentration in the atmosphere leads to the change of meteorological transmission, eventually leading to the reduction of O concentration in Beijing. In conclusion, this study highlights the importance of atmospheric chemistry for air quality models to model atmospheric pollutants and should attract more research focus.
确定大气化学机制的准确性是空气污染预测、污染成因分析和基于空气质量模型模拟制定控制方案的关键因素。然而，在 MOZART-4 化学机制中，通常忽略 NH 和 OH 反应生成 NH 及其随后的反应。为了解决这个问题，本研究更新了 NH 的气相化学机制。响应面法（RSM）、综合气相反应速率（IRR）诊断和过程分析（PA）用于量化更新的 NH 化学机制对模拟的 O 浓度、O 及其前体的非线性响应关系、O 生成的化学反应速率和气象传输过程的影响。结果表明，更新的 NH 化学机制可以减少模拟和观测到的 O 浓度之间的误差，并更好地模拟 O 浓度。与 Base 情景（原始化学机制模拟）相比，RSM 中 Updated 情景（更新的 NH 化学机制模拟）中 NH 的一阶项通过了显著性检验（p<0.05），表明 NH 排放对 O 模拟有影响，更新的 NH 化学机制对不同城市的 NOx-VOC-O 的影响也不同。此外，化学反应速率变化分析表明，NH 通过影响 OH 和 HO 自由基的 NOx 浓度和 NOx 循环，可影响 O 的生成，大气中污染物浓度的变化导致气象传输的变化，最终导致北京 O 浓度的降低。总之，本研究强调了大气化学对空气质量模型模拟大气污染物的重要性，应引起更多的研究关注。
