Lightning-generated nitrogen oxides (LNOx) have an impact on the concentration of ground-level ozone which acts as a toxic air pollutant, thereby negatively influencing human health and the environment. To understand the impact of LNOx on ground-level ozone, we simulated four thunderstorm events in Tehran using the WRF-Chem model. As observations of LNOx are not available, we evaluated the temporal distribution of the simulated ground-level ozone concentration against an air quality monitoring station. We also compared the simulation results against the spatial distribution of the total column ozone from the Ozone Monitoring Instrument. WRF-Chem performs well in the simulation of ground-level ozone concentration, with the best performance for an event with the highest lightning activity (correlation coefficient of 0.91). The analysis of the spatial distribution of the observed and simulated total column ozone also indicates the good performance of WRF-Chem. Hourly variation in the simulated LNOx during lightning activity is compared against both hourly variation in the observed ground-level ozone and the number of lightning for four thunderstorm events. There is an agreement between the simulated LNOx and the observed ground-level ozone during lightning for two events, with correlation coefficients of 0.55 and 0.57. LNOx emissions enhance ozone production in the middle to upper troposphere, which can subsequently contribute to an increase in ground-level ozone by transport, vertical mixing, and chemistry. In addition, the initiation of chemical processes in response to cloud-to-ground lightning strikes may contribute to an increase in both LNOx and the concentration of ground-level ozone.

中文翻译：

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闪电氮氧化物的产生对德黑兰地面臭氧的影响

闪电产生的氮氧化物 (LNOx) 会影响地面臭氧的浓度，而臭氧是一种有毒空气污染物，从而对人类健康和环境产生负面影响。为了了解 LNOx 对地面臭氧的影响，我们使用 WRF-Chem 模型模拟了德黑兰的四次雷暴事件。由于无法获得 LNOx 的观测结果，我们根据空气质量监测站评估了模拟地面臭氧浓度的时间分布。我们还将模拟结果与臭氧监测仪器的总柱臭氧的空间分布进行了比较。WRF-Chem 在模拟地面臭氧浓度方面表现良好，在闪电活动最高的事件中表现最佳（相关系数为 0.91）。对观测和模拟总柱臭氧空间分布的分析也表明了WRF-Chem的良好性能。将闪电活动期间模拟 LNOx 的每小时变化与观测到的地面臭氧的每小时变化以及四次雷暴事件的闪电数量进行比较。对于两次事件，模拟的 LNOx 与闪电期间观测到的地面臭氧之间存在一致性，相关系数分别为 0.55 和 0.57。LNOx 排放增强了对流层中上层的臭氧产生，随后通过传输、垂直混合和化学作用导致地面臭氧增加。此外，响应云对地雷击而引发的化学过程可能会导致 LNOx 和地面臭氧浓度的增加。