CO2 concentrations and air change rates in Chinese city-type residences

Yuina Fujii, U. Yanagi, Hiroshi Yoshino, Zhenhai Li, Huibo Zhang, Jing Chao Xee, Yang Lv, Jing Liu, Shengwei Zhu, Niapen Li, Kenichi Hasegawa, Naoki Kagi, Tomonobu Goto

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Carbon dioxide concentration (CO2) is an important index for estimating the air exchange rate (AER). To clarify the actual conditions of the AERs in city-type residences in China, CO2 concentrations were measured at 5-minute intervals during a period of one to two weeks in six cities (Harbin, Dalian, Beijing, Shanghai, Wuhan, and Changsha) in summer and winter. The AERs were estimated by the reciprocal average concentration method and the CO2 fitting technique, both of which rely on measured CO2 concentrations. The ranges of CO2 concentrations in winter and summer were 400-9794 ppm and 400-4519 ppm, respectively. The difference of the minimum concentrations was not remarkable between winter and summer among the six cities because indoor CO2 concentrations are strongly influenced by outdoor CO2 concentrations. On the other hand, for the maximum concentrations, winter showed CO2 concentrations higher than those in summer. This finding indicates that the residents do not frequently open their windows in winter, and so indoor CO2 concentrations trend to a high value. As estimated by the CO2 fitting technique, it became clear that when windows were closed, AERs were 0.5 h-1 or less. In the city-type residences in China, the CO2 concentrations at the time of sleeping with closed windows reached a maximum of 10,000 ppm around daybreak, since airtightness was also higher. However, since windows are customarily opened in the daytime, the lowest concentrations in the daytime were comparable with the outdoor air concentrations in both summer and winter.

Original languageEnglish
Title of host publicationVentilation 2015 - Proceedings of the 11th International Conference on Industrial Ventilation
EditorsAimo Taipale, Zhengrong Li, Xianting Li, Xu Zhang
PublisherInternational Conference on Industrial Ventilation
Pages1000-1007
Number of pages8
ISBN (Electronic)9780000000002
Publication statusPublished - 2015 Jan 1
Event11th International Conference on Industrial Ventilation, Ventilation 2015 - Shanghai, China
Duration: 2015 Oct 262015 Oct 28

Publication series

NameVentilation 2015 - Proceedings of the 11th International Conference on Industrial Ventilation
Volume2

Other

Other11th International Conference on Industrial Ventilation, Ventilation 2015
CountryChina
CityShanghai
Period15/10/2615/10/28

Keywords

  • Air exchange rate
  • CO concentration
  • CO fitting technique
  • Reciprocal average concentration method
  • Residence

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Civil and Structural Engineering
  • Building and Construction
  • Control and Systems Engineering

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