Personal CO 2 cloud: laboratory measurements of metabolic CO 2 inhalation zone concentration and dispersion in a typical office desk setting.

摘要

Inhalation exposure to pure and metabolic elevated carbon dioxide (CO_(2)) concentration has been associated with impaired work performance, lower perceived air quality, and increased health symptoms. In this study, the concentration of metabolic CO_(2)was continuously measured in the inhalation zone of 41 subjects performing simulated office work. The measurements took place in an environmental chamber with well-controlled mechanical ventilation arranged as an office environment. The results showed the existence of a personal CO_(2)cloud in the inhalation zone of all test subjects, characterized by the excess of metabolic CO_(2)beyond the room background levels. For seated occupants, the median CO_(2)inhalation zone concentration levels were between 200 and 500?ppm above the background, and the third quartile up to 800?ppm above the background. Each study subject had distinct magnitude of the personal CO_(2)cloud owing to differences in metabolic CO_(2)generation, posture, nose geometry, and breathing pattern. A small desktop oscillating fan proved to be suitable for dispersing much of the personal CO_(2)cloud, thus reducing the inhalation zone concentration to background level. The results suggest that background measurements cannot capture the significant personal CO_(2)cloud effect in human microclimate.