In this study, fifteen participants were exposed to different carbon dioxide (CO₂) concentrations in an enclosed environmental chamber to investigate the potential effects of elevated CO₂ concentrations on human vigilance and sentiment. The psychomotor vigilance test (PVT), the Karolinska Sleepiness Scale (KSS), and the Positive and Negative Affect Schedule (PANAS) were measured before and after each 4‐hour CO₂ exposure session. The statistical analyses of the PVT performance metrics showed that the human vigilance decreased significantly with the elevated CO₂ concentration from 1500 ppm to above 3500 ppm, but no significant change was observed in the KSS score. Moreover, although the participants reported less positive and more negative emotions as the CO₂ exposure concentration increased, the effect of CO₂ concentration on human sentiment was not potent. In sum, the findings suggested a detrimental effect of CO₂ exposure concentration on human vigilance at the CO₂ concentration of 3500 ppm, which is below the current occupational exposure limit of 5000 ppm. It is worth noting that the order of CO₂ exposures was not balanced among the participants, which remains a major limitation of this study.

中文翻译：

---

封闭工作环境中二氧化碳暴露浓度对人类警觉性和情绪的影响

在这项研究中，十五名参与者在封闭的环境室中暴露于不同浓度的二氧化碳 (CO ₂ ) 中，以研究 CO ₂浓度升高对人类警觉性和情绪的潜在影响。在每个 4 小时 CO ₂暴露会话之前和之后测量精神运动警觉性测试 (PVT)、卡罗林斯卡嗜睡量表 (KSS) 和积极和消极影响表 (PANAS) 。PVT 性能指标的统计分析表明，随着 CO ₂的升高，人类的警惕性显着降低浓度从 1500 ppm 到 3500 ppm 以上，但 KSS 得分没有观察到显着变化。此外，尽管随着 CO ₂暴露浓度的增加，参与者报告的积极情绪减少而消极情绪增加，但 CO ₂浓度对人类情绪的影响并不明显。总之，研究结果表明，当 CO ₂浓度为 3500 ppm 时，CO ₂暴露浓度对人类警觉性有不利影响，这低于当前的职业暴露限值 5000 ppm。值得注意的是，参与者之间的CO ₂暴露顺序并不平衡，这仍然是本研究的主要局限性。