Shihezi City has experienced severe ozone pollution. The vertical observation of ozone precursors (NO and HCHO) and SO in this area was conducted by multi-axis differential optical absorption spectroscopy in summer, 2023. During this experiment, ozone was measured at an average concentration of 94.89 ± 37.46 μg/m, and it mainly increased when the northerly wind dominated, accompanied by the increasing of its precursors. In addition, SO had a relatively high concentration and elevated with the rising ozone concentration, remarkably different from other cities in China. The average vertical distribution of HCHO in the ozone pollution period was a Gaussian type, with the peak value at about 0.2 km. In contrast, the vertical distribution of NO and SO decreased exponentially with the rise of vertical height, and their concentrations dropped rapidly within 0–1 km. The R range of the transitional regime in Shihezi City was [1.26, 2.80]. Given that ozone pollution mostly occurred when R was 1–2, the chemical production of near-surface ozone in Shihezi City was controlled by a transition regime. The R vertical pattern was Gaussian type and reached a maximal value at 400–600 m. R increased at the middle altitude (0.4–1.2 km), and the ozone formation was controlled by the transitional regime. R decreased above 1.2 km, and the photochemical ozone formation was mainly controlled by a VOCs-limited regime. This study provides an improved understanding of O precursors vertical distribution and O formation sensitivity in Shihezi City.

中文翻译：

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石河子市夏季HCHO、NO2、SO2 O3敏感性及垂直分布

石河子市臭氧污染严重。 2023年夏季，利用多轴差分光吸收光谱对该区域的臭氧前体物（NO和HCHO）和SO进行了垂直观测。实验过程中，测得臭氧平均浓度为94.89±37.46 μg/m，主要在偏北风主导时增加，并伴随其前兆的增加。另外，SO浓度较高，且随臭氧浓度升高而升高，与国内其他城市明显不同。臭氧污染期间HCHO的平均垂直分布呈高斯型，峰值在0.2 km左右。相比之下，NO和SO的垂直分布随着垂直高度的升高呈指数下降，且浓度在0~1 km内迅速下降。石河子市过渡政权的R范围为[1.26,2.80]。鉴于臭氧污染主要发生在R为1~2时，石河子市近地表臭氧化学生成受过渡制度控制。 R垂直方向图呈高斯型，在400~600 m处达到最大值。 R在中海拔（0.4-1.2公里）增加，臭氧形成受过渡状态控制。 R 下降到 1.2 km 以上，光化学臭氧的形成主要受 VOCs 限制机制控制。本研究加深了对石河子市 O 前体垂直分布和 O 形成敏感性的了解。