High indoor CO₂concentrations in an office environment increases the transcutaneous CO₂level and sleepiness during cognitive work

Abstract

The purpose of this study is to perform a multiparametric analysis on the environmental factors, the physiological stress reactions in the body, the measured alertness, and the subjective symptoms during simulated office work. Volunteer male subjects were monitored during three 4-hr work meetings in an office room, both in a ventilated and a non-ventilated environment. The environmental parameters measured included CO(2), temperature, and relative humidity. The physiological test battery consisted of measuring autonomic nervous system functions, salivary stress hormones, blood's CO(2)- content and oxygen saturation, skin temperatures, thermal sensations, vigilance, and sleepiness. The study shows that we can see physiological changes caused by high CO(2) concentration. The findings support the view that low or moderate level increases in concentration of CO(2) in indoor air might cause elevation in the blood's transcutaneously assessed CO(2). The observed findings are higher CO(2) concentrations in tissues, changes in heart rate variation, and an increase of peripheral blood circulation during exposure to elevated CO(2) concentration. The subjective parameters and symptoms support the physiological findings. This study shows that a high concentration of CO(2) in indoor air seem to be one parameter causing physiological effects, which can decrease the facility user's functional ability. The correct amount of ventilation with relation to the number of people using the facility, functional air distribution, and regular breaks can counteract the decrease in functional ability. The findings of the study suggest that merely increasing ventilation is not necessarily a rational solution from a technical-economical viewpoint. Instead or in addition, more comprehensive, anthropocentric planning of space is needed as well as instructions and new kinds of reference values for the design and realization of office environments.

Environmental perceptions and health before and after relocation to a green building

“…Historically CO 2 exposures below 5000 ppm were not anticipated to affect blood CO 2 levels, but recent findings by Vehvilainen et al show linear increases in the partial pressure of CO 2 in blood (pCO 2 ) as exposures to ambient CO 2 were increased from 500 ppm to 4000 ppm through changes in ventilation rate. They also see other physiological responses consistent with increased sympathetic stimulation including changes to heart rate variability and increases to peripheral blood circulation [26]. Another study by Kajtar and Herczeg, which exposed participants to levels of CO 2 ranging from 600 ppm to 5000 ppm, supports our findings and those by Vehvilainen.…”

Real-time monitoring of personal exposures to carbon dioxide

“…Vehviläinen et al [30] report that exposures to elevated CO2 result in higher concentrations of CO2 in body tissues, changes in heart rate variation, and increases in peripheral blood circulation in subjects. These changes coincided with increases in subjective assessments of sleepiness and incidence of headache.…”

The impact of working in a green certified building on cognitive function and health

“…We found significant impacts on human decision-making performance related to all three of these factors (Allen et al, 2015). Others have also found independent effects of ventilation, CO 2 and VOCs on cognitive function and other physiological responses at levels commonly found in indoor environments [19, 28–31]. In this current study, we looked at buildings that are high-performing across these indicators of IEQ and investigated the potential for additional benefits of green certification on cognitive function, environmental perceptions, and health.…”