The effects of carbon dioxide exposure concentrations on human vigilance and sentiment in an enclosed workplace environment

Abstract

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 1500ppm to above 3500ppm, 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 3500ppm, which is below the current occupational exposure limit of 5000ppm. It is worth noting that the order of CO2 exposures was not balanced among the participants, which remains a major limitation of this study.