Investigation of Indoor Air Quality in six office buildings in Chengdu, China based on continuous monitoring data

Abstract

Indoor air pollution is of a growing concern in China. The nation's growing urban work force spends prolonged periods in office, thus office indoor air quality (IAQ) can be a key determinant of worker's wellbeing, yet, IAQ literature on China's office space remains scarce. To address such knowledge gap, this study conducted continuous monitoring in six office towers in Chengdu, China to investigate two major indoor pollutants: PM2.5 and CO2. The participating office buildings were Grade-A certified and fully occupied. Indoor concentration for PM2.5 and CO2 ranged between 1-459 μg/m3 and 375-1102 ppm respectively, with considerable intra-building and inter-building variability. Time-series analysis suggests diurnal and weekly pattern for indoor CO2, and temporal association between indoor and ambient PM2.5. Filtration and ventilation efficiencies varied across buildings, and these buildings experienced various degrees of penetration by outdoor PM2.5 and indoor accumulation of CO2 on a daily basis. On days with ambient pollution, indoor pollution persisted. Multivariate model predicts an average of 0.6 μg/m3 increase in indoor PM2.5 for every 1 μg/m3 increase in ambient PM2.5. To our knowledge, this is the first systematic study of office buildings in China with findings potentially inform future IAQ management strategies.