Air Change Rates in Residential Buildings in Tianjin, China.

Air change rate is an important factor in indoor environment with regards to occupants’ health. In order to study the association of air change rate in homes and building characteristics, a large scale air change rate measurements were carried out during Sept. 2013-Jan. 2016 in Tianjin, China. 410 homes were investigated and indoor environment were measured. Carbon dioxide concentration in homes was continuously measured for 24 hours. Air change rate was calculated by using CO 2 produced by occupants as tracer gas. In the whole home, air change rates during sleeping time averaged 0.61±1.05 h -1 (median=0.32 h -1 , n=340). In the bedrooms, air change rate during sleeping time were substantially higher, averaging 0.81±1.33 h -1 (median=0.43 h -1 , n=390). Months trends of whole home and bedroom air change rates differed. Air change rates were higher in smaller homes. Formaldehyde and TVOC concentration in homes with higher air change rate were lower. [ABSTRACT FROM AUTHOR]