Publication date: Available online 17 February 2016
Source:Building and Environment
Author(s): Xiaojing Zhang, Pawel Wargocki, Zhiwei Lian
To extend the results of a previous study on the effects of carbon dioxide (CO2 ) and bioeffluents on humans, the new study reported in this paper was carried out. The purpose of this study was to examine, whether exposure to CO2 at 5,000 ppm would cause sensory discomfort, evoke acute health symptoms, reduce the performance of cognitive tasks, or result in changes in physiological responses. The outdoor air supply rate was set high enough in a low-emission stainless-steel climate chamber to create a reference condition with CO2 at 500 ppm when subjects were present, and chemically pure CO2 was added to the supply air to create an exposure condition with CO2 at 5,000 ppm (the measured exposure level was ca. 4,900 ppm). Ten healthy college-age students were exposed twice to each of the two conditions for 2.5 hours in a design balanced for order of presentation. The raised CO2 concentration had no effect on perceived air quality or physiological responses except for end-tidal CO2 (ETCO2 ), which increased more (to 5.3 kPa) than it was in the reference condition (5.1 kPa). Other results indicate additionally that a 2.5-hour exposure to CO2 up to 5,000 ppm did not increase intensity of health symptoms reported by healthy young individuals and their performance of simple or moderately difficult cognitive tests and some tasks resembling office work. These results accord well with the current occupational exposure limit recommendation for CO2 and with many other reports published in the literature.
Source:Building and Environment
Author(s): Xiaojing Zhang, Pawel Wargocki, Zhiwei Lian