Ground-level ozone is a secondary pollutant produced by photochemical reactions and it adversely affects plant and human health. Taiyuan City, a typical city on the loess plateau, is suffering from severe ozone pollution. We utilized the data from eight national environmental monitoring sites of Taiyuan, including concentrations of O₃ and nitric oxide, and meteorological factors, such as air temperature and wind, to study the pollution characteristics and sources of ozone (O₃) in Taiyuan in 2018. Results show that during 2018, the maximum value and 90th percentile of the maximum 8-h running average of O₃ concentration were 257 μg/m³ and 192 μg/m³, respectively. There were 72 days where the O₃ concentration exceeded the standard in 2018, which were mainly during April to August. The O₃ concentration increased from March, reached a high level in April through August, and decreased significantly from September. The O₃ concentrations displayed a typical “single peak” diurnal variation, which was high during the day with peak at around 13:00-15:00 and low at night. From April to August, the O₃ concentrations at Jinyuan was the highest, followed by Xiaodian and Taoyuan, and the O₃ concentrations at Shanglan and Nanzhai were the lowest. When the O₃ concentration exceeded the standard value, Jinyuan contributed the most to the O₃ pollution of Taiyuan, followed by Taoyuan and Xiaodian. High temperature and pressure, south and southwest winds can lead to an increase in O₃ concentration. The O₃ pollution in the Taiyuan urban area is caused by local generation, and the transportation of polluted air masses containing oxides of nitrogen (NOx) and volatile organic compounds (VOCs) emitted by industries, such as the coking and steel plants in counties of Jinzhong City in southern Taiyuan, and Qingxu County, and some counties in Lyuliang City to the southwest. In addition, the mountain winds and low nitric oxide concentration are the main reasons for the increase of O₃ concentration, often observed in Shanglan at night.

中文翻译：

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黄土高原典型城区臭氧污染特征及来源研究。

地面臭氧是光化学反应产生的二次污染物，对植物和人类健康产生不利影响。黄土高原上的典型城市太原市正遭受着严重的臭氧污染。我们利用太原市8个国家环境监测站的数据，包括O ₃和一氧化氮的浓度以及气温和风等气象因素，研究了2018年太原市的污染特征和臭氧（O ₃）来源。结果显示，在2018年期间，O ₃浓度的最大8小时运行平均值的最大值和最大百分位数分别为257μg/m³和192μg/m³。有72天的O ₃浓度超过了2018年的标准，主要在4月至8月。O ₃浓度从3月开始增加，从4月到8月达到高水平，从9月开始显着下降。O ₃浓度表现出典型的“单峰”日变化，白天高，峰值在13：00-15：00左右，晚上低。4至8月，金源的O ₃浓度最高，其次是小店和桃园，上兰和南寨的O ₃浓度最低。当O ₃浓度超过标准值时，金源对O _3的贡献最大太原污染，其次是桃园和小店。高温和高压，南风和西南风会导致O ₃浓度增加。太原市区的O ₃污染是由当地产生的，以及污染源的运输，这些污染源包括工业化县（如焦化和钢铁厂）排放的氮氧化物（NOx）和挥发性有机化合物（VOC）。太原市南部的晋中市和西南部的吕梁市的清徐县及部分县。此外，山风和一氧化氮浓度低是O ₃浓度增加的主要原因，通常在晚上在上兰观察到。