title: Indoor formaldehyde concentrations in urban China: Preliminary study of some important influencing factors.
abstract: The Huai River and Qingling Mountain divide (H-Q) divide China into north and south with respect to public policies for building construction and operation practises. China's building energy efficiency standard mandates that air exchange rates be 0.5h-1north of the H-Q divide and 1h-1south of the divide. China's heating policy allows space heating systems only north of the H-Q divide. Consequently, indoor temperature and humidity differ considerably between north and south. A theoretical model using indoor temperature, humidity, and air change rate was developed to predict indoor formaldehyde concentrations. Data for 39 cities were obtained from 42 studies. There was good agreement between the literature and modelling in a theoretical reference room. The United States Environmental Protection Agency (U.S.EPA) model was applied to estimate cancer risk from formaldehyde exposure indoors. The median indoor formaldehyde concentration for renovation ever from 2002 to 2015 in Chinese cities was 125μg/m3, which is higher than the WHO threshold, 100μg/m3. The median indoor formaldehyde concentrations in the north were higher than in the south (0.5 times higher for dwellings renovated within the past year and 0.2 times higher for renovation ever), driven by the much higher northern winter concentrations (40-1320%). The U.S.EPA model predicts that the lifetime formaldehyde related cancer risk for people living north of the H-Q divide is 1.2 times greater than for people living south. This can be partly explained by greater indoor exposure to formaldehyde for Chinese living north of the H-Q divide.
authors.affiliation: Department of Building Science, Tsinghua University, Beijing 100084, China; Beijing Key Lab of Indoor Air Quality Evaluation and Control, Beijing 100084, China; Department of Environmental Science, Harvard T.H. Chan School of Public Health, Boston 02115, USA.
authors.forename: Shaodan
authors.initials: S
authors.lastname: Huang
authors.affiliation: Department of Building Science, Tsinghua University, Beijing 100084, China; University of Paris-Est, Scientific and Technical Center for Building (CSTB), Health and Comfort Department, French Indoor Air Quality Observatory (OQAI), 84 Avenue Jean Jaurès, Champs sur Marne, 77447 Marne la Vallée Cedex 2, France.
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Wei
authors.affiliation: Department of Building Science, Tsinghua University, Beijing 100084, China; Independent Researcher, 161 Richdale Road, Colts Neck, NJ 07722, USA.
authors.forename: Louise B
authors.initials: LB
authors.lastname: Weschler
authors.affiliation: Fraunhofer WKI, Department of Material Analysis and Indoor Chemistry, 38108 Braunschweig, Germany.
authors.forename: Tunga
authors.initials: T
authors.lastname: Salthammer
authors.affiliation: School of Public Health, Fudan University, Shanghai 200032, China.
authors.forename: Haidong
authors.initials: H
authors.lastname: Kan
authors.affiliation: Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China.
authors.forename: Zhongming
authors.initials: Z
authors.lastname: Bu
authors.affiliation: Department of Building Science, Tsinghua University, Beijing 100084, China; Beijing Key Lab of Indoor Air Quality Evaluation and Control, Beijing 100084, China. Electronic address: zhangyp@tsinghua.edu.cn.
authors.forename: Yinping
authors.initials: Y
authors.lastname: Zhang
keywords: Building energy efficiency; Indoor air quality; Indoor formaldehyde exposure; Ventilation