Effects of exposure to carbon dioxide and bioeffluents on perceived air quality, self-assessed acute health symptoms, and cognitive performance

Abstract

The purpose of this study was to examine the effects on humans of exposure to carbon dioxide (CO ) and bioeffluents. In three of the five exposures, the outdoor air supply rate was high enough to remove bioeffluents, resulting in a CO level of 500 ppm. Chemically pure CO was added to this reference condition to create exposure conditions with CO at 1000 or 3000 ppm. In two further conditions, the outdoor air supply rate was restricted so that the bioeffluent CO reached 1000 or 3000 ppm. The same 25 subjects were exposed for 255 min to each condition. Subjective ratings, physiological responses, and cognitive performance were measured. No statistically significant effects on perceived air quality, acute health symptoms, or cognitive performance were seen during exposures when CO was added. Exposures to bioeffluents with CO at 3000 ppm reduced perceived air quality; increased the intensity of reported headache, fatigue, sleepiness, and difficulty in thinking clearly; and reduced speed of addition, the response time in a redirection task, and the number of correct links made in the cue-utilization test. This suggests that moderate concentrations of bioeffluents, but not pure CO , will result in deleterious effects on occupants during typical indoor exposures.

Human responses to carbon dioxide, a follow-up study at recommended exposure limits in non-industrial environments

“…The chamber was thoroughly cleaned prior to the experiments and 'baked' for one week at a temperature of 40°C to reduce any residual pollution on the inner surfaces of the chamber and its ducting. No chemical measurements were performed prior to the experiment to examine whether the background pollution level was in fact low, but many previous experiments performed in the same chamber have documented that the chamber is indeed low-emitting (e.g., Fang et al, 1998a,b;Kjaergaard et al, 1999;Pejtersen et al, 2001;Zhang et al, 2016b). The sensory assessments of air quality made by the subjects in the present experiment (see the Results section and Fig.…”

“…The experiment was carried out in the climate chamber described in detail by Albrechtsen (1988) and Zhang et al (2016b). The chamber is made of stainless steel.…”

“…Another reason for selecting this temperature was to match the thermal condition with an experiment that examined the effects of elevated temperature (35°C) and the combined effects of elevated temperature and CO 2 (Liu and Wargocki, 2015;Liu et al, 2016). Subjective measurements were carried out using the same questionnaires as were used in the previous study by Zhang et al (2016b). They included questions regarding perception of indoor environment, including the acceptability of the air quality, odour intensity, air freshness, thermal sensation and acceptability of thermal environment, air dryness, brightness and noise level.…”

Volatile Organic Compound Emissions from Humans Indoors

“…1 Although there have been changes over time, 50 human perception and subjective assessment of the acceptability of indoor air remains an 51 important basis for current ventilation standards and practice. 2 In turn, building ventilation rates 52 matter for at least two major reasons: (a) they are related to public health and well being 3,4 and 53 (b) they contribute substantially to energy use in buildings and consequently to total energy 54 use.…”

Window and door opening behavior, carbon dioxide concentration, temperature, and energy use during the heating season in classrooms with different ventilation retrofits—ASHRAE RP1624

“…The measured CO 2 concentrations were below the 8-hour maximum permissible occupational exposure level of 5000 ppm (OSHA 2017). Also, there is no conclusive evidence that CO 2 itself among adults should increase the risk of discomfort or health problems or the cognitive performance of simple tasks (Liu et al 2017;Zhang et al 2016Zhang et al , 2017, although demanding cognitive tasks have been shown to be affected (Allen et al 2016;Satish et al 2012). CO 2 at the concentrations measured in the current study should thus not be considered a toxic compound.…”