Laser-induced breakdown spectroscopy (LIBS) is regarded as the future superstar for analytical chemistry and widely applied in various fields. Improving the quality of LIBS signal is fundamental to achieving accurate quantification and large-scale commercialization of LIBS. To propose control methods that improve LIBS signal quality, it is essential to have a comprehensive understanding of the influence of key parameters, such as ambient gas pressure, temperature, and sample temperature on LIBS signals. To date, extensive research has been carried out. However, different researchers often yield significantly different experimental results for LIBS, preventing the formation of consistent conclusions. This greatly prevents the understanding of influencing laws of key parameters and the improvement of LIBS quantitative performance. Taking ambient gas pressure as an example, this paper compares the effects of ambient gas pressure under different optimization conditions, reveals the influence of spatiotemporal window caused by inherent characteristics of LIBS signal sources, i.e., intense temporal changes and spatial non-uniformity of laser-induced plasmas, on the impact patterns of key parameters. From the perspective of plasma spatiotemporal evolution, the paper elucidates the influence patterns of ambient gas pressure on LIBS signals, clarifying seemingly contradictory research results in the literature.

激光诱导击穿光谱（LIBS）被认为是分析化学的未来超级明星，广泛应用于各个领域。提高LIBS信号质量是实现LIBS准确定量和大规模商业化的基础。为了提出提高 LIBS 信号质量的控制方法，必须全面了解环境气压、温度和样品温度等关键参数对 LIBS 信号的影响。迄今为止，已经进行了广泛的研究。然而，不同的研究人员常常会得出明显不同的 LIBS 实验结果，从而无法形成一致的结论。这极大地阻碍了关键参数影响规律的理解和LIBS定量性能的提高。以环境气压为例，比较了不同优化条件下环境气压的影响，揭示了LIBS信号源固有特性，即激光强烈的时间变化和空间不均匀性对时空窗口的影响。诱导等离子体对关键参数的影响模式。论文从等离子体时空演化的角度出发，阐明了环境气压对LIBS信号的影响模式，澄清了文献中看似矛盾的研究结果。