The vertical variations and key drivers of ozone and its precursors, namely NOx and VOCs, in the atmospheric boundary layer, have vital impacts on surface ozone budgets but are poorly understood so far. Using online gradient measurements from a 356 m tower, we obtained continuous vertical profiles of ozone and its precursors, which exhibited strong gradients throughout the day. In the daytime, the vertical gradients of ozone precursors are significantly regulated by reactions with OH radicals. At night, our observations confirmed more intense VOC reactions with NO₃ radicals in the residual layer than in the boundary layer. Additionally, we found that residual layer entrainment could contribute to over half of the boundary-layer ozone enhancements in the morning periods. Our results underscore the importance of considering vertical changes of ozone and its precursors in the atmospheric boundary layer when developing future ozone mitigation strategies.

臭氧及其前体物（即 NOx 和 VOC）在大气边界层中的垂直变化和关键驱动因素对地表臭氧收支有至关重要的影响，但迄今为止人们对此知之甚少。使用来自 356 m 塔的在线梯度测量，我们获得了臭氧及其前体物的连续垂直剖面，这些臭氧及其前体物全天表现出强烈的梯度。在白天，臭氧前体的垂直梯度受到与 OH 自由基反应的显着调节。晚上，我们的观察证实，残留层中 NO₃ 自由基的 VOC 反应比边界层更强烈。此外，我们发现残余层夹带可能导致早上边界层臭氧增强一半以上。我们的结果强调了在制定未来的臭氧缓解策略时考虑臭氧及其前体物在大气边界层中的垂直变化的重要性。