Carbon dioxide generation rates and subjects’ perception of air quality of office activities under various ambient temperatures

¹ Xi’an University of Architecture and Technology, China.
² State Key Laboratory of Green Building in Western China, Xi’an University of Architecture and Technology, Xi’an, Shanxi, 710055, China

^* Corresponding author: zhaiyongchao@xauat.edu.cn

Abstract

Indoor carbon dioxide (CO₂) concentration is an important parameter that has been used to characterize and design indoor air quality and building ventilation. In indoor spaces, the primary source of CO₂ is occupants, and the rate is always related to occupants’ activities intensity. However, the CO₂ generation rates required by many applications were currently calculated by metabolic rates using equations given in the ASHRAE Handbook, which were based on the average of adults from Europe and North America that are several decades old. In addition, the ambient temperatures may also affect CO₂ generation rates by affecting human metabolic reactions but were not considered. There is little systematic experimental determination of human CO₂ generation rates at different activity levels and various ambient temperatures. This study experimentally determines Chinese office people’s CO₂ generation rates by 28 college students (14 women and 14 men) aged 20~30, while conducting office tasks (sitting and typing, standing and typing, walking at 1 km/h, and walking at 2 km/h) at 20, 23, 26, and 29 ℃. CO₂ generation rates increase significantly as activity levels increase, and slightly increased with increasing ambient temperature. With activity intensity increases, the gender and temperature differences also grow.