Secondary inorganic aerosol (SIA) is the key driving factor of fine-particle explosive growth (FPEG) events, which are frequently observed in North China Plain. However, the SIA simulations remain highly uncertain over East Asia. To further investigate this issue, SIA modeling over North China Plain with the 15 km resolution Nested Air Quality Prediction Model System (NAQPMS) was performed from October 2017 to March 2018. Surface observations of SIA at 28 sites were obtained to evaluate the model, which confirmed the biases in the SIA modeling. To identify the source of these biases and reduce them, uncertainty analysis was performed by evaluating the heterogeneous chemical reactions in the model and conducting sensitivity tests on the different reactions. The results suggest that the omission of the SO₂ heterogeneous chemical reaction involving anthropogenic aerosols in the model is probably the key reason for the systematic underestimation of sulfate during the winter season. The uptake coefficient of the “renoxification” reaction is a key source of uncertainty in nitrate simulations, and it is likely to be overestimated by the NAQPMS. Consideration of the SO₂ heterogeneous reaction involving anthropogenic aerosols and optimization of the uptake coefficient of the “renoxification” reaction in the model suitably reproduced the temporal and spatial variations in sulfate, nitrate and ammonium over North China Plain. The biases in the simulations of sulfate, nitrate, ammonium, and particulate matter smaller than 2.5 μm (PM_2.5) were reduced by 84.2%, 54.8%, 81.8%, and 80.9%, respectively. The results of this study provide a reference for the reduction in the model bias of SIA and PM_2.5 and improvement of the simulation of heterogeneous chemical processes.

中文翻译：

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华北平原秋冬季次生无机气溶胶模拟的评估与偏差校正

次生无机气溶胶（SIA）是细颗粒炸药生长（FPEG）事件的关键驱动因素，在华北平原上经常观察到这种现象。但是，在东亚地区的SIA模拟仍然高度不确定。为了进一步调查该问题，于2017年10月至2018年3月使用15 km分辨率的嵌套空气质量预测模型系统（NAQPMS）对华北平原进行了SIA建模。获得了28个站点的SIA地面观测以评估模型。确认了SIA建模中的偏见。为了确定这些偏差的来源并减少偏差，通过评估模型中的异质化学反应并对不同的反应进行敏感性测试来进行不确定性分析。结果表明，SO ₂的遗漏模型中涉及人为气溶胶的异质化学反应可能是冬季系统性低估硫酸盐的主要原因。“重新氧化”反应的吸收系数是硝酸盐模拟中不确定性的一个关键来源，很可能会被NAQPMS高估。考虑模型中涉及人为气溶胶的SO ₂异相反应和优化“重新氧化”反应的吸收系数，该模型适当地再现了华北平原上硫酸盐，硝酸盐和铵盐的时空变化。硫酸盐，硝酸盐，铵和小于2.5μm（PM _2.5）分别减少了84.2％，54.8％，81.8％和80.9％。研究结果为减少SIA和PM _2.5的模型偏差以及改进异构化学过程的模拟提供了参考。