Assessing the seasonality of occupancy number-associated CO2 level in a Taiwan hospital

  • Yi-Chen Li
  • Wen-Chang Tseng
  • Nan-Hung Hsieh
  • Szu-Chieh ChenEmail author
Research Article


This study enabled the assessment of indoor CO2 levels and evaluated the relationship between occupancy numbers with CO2 levels in a Taiwan hospital. The measurements were conducted over four seasons for five working days (Monday to Friday), with sampling conducted simultaneously from 09:00 am to 5:00 pm and across six locations (for spatial variability): hall (H), registration and cashier (RC), waiting area (WA), occupational therapy room (OT), physical therapy room (PT), and outdoors (O). Based on the analysis, three of the five indoor sampling sites showed significant differences in seasonal CO2 concentrations (p < 0.0001). Based on our result, the physical therapy room had the highest level of CO2 concentration that exceeded the IAQ standard in Taiwan Environmental Protection Agency (EPA) in all seasons, in that the number of occupants contributing to nearly 40% of the variation in CO2 measured. Our results also showed that the indoor/outdoor (I/O) ratios of CO2 concentration for all locations and seasons exceeded 1 in ~ 100% of those locations. The median I/O ratio at sites WA and OT was 2.37 and 2.08 during four seasons, respectively. The highest median I/O ratio was found at site PT, with a calculated range of 2.69 in spring to 3.90 in fall. The highest correlation of occupancy number and CO2 concentration also occurred in PT which correlation coefficients were estimated at 0.47, 0.65, 0.63, and 0.40 in spring, summer, fall, and winter. The findings of the present study can be used to understand occupancy number and its effect on CO2 levels in a hospital environment, as well as the effect of time of day (Monday to Friday) on the number of patients admitted.


Occupancy number Indoor air quality CO2 level Season I/O ratio Hospital 



The authors thank Yuan Rung Hospital for their willingness to provide us the study area.

Author contributions

Y.C. (Yi-Chen) conducted the experiments and W.C. (Wen-Chang) performed the statistical analysis; N.H. (Nan-Hung) and S.C. (Szu-Chieh) wrote the paper.

Funding information

This work was supported by the Ministry of Science and Technology of the Republic of China under Grant MOST 107-2313-B-040-001.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no competing interests.

Research involving human participants and animal rights

This study was approved by the Institutional Review Board of the Ethical Committee of Chung Shan Medical University (CSMUH No: CS16072).

Supplementary material

11356_2019_5084_MOESM1_ESM.docx (237 kb)
ESM 1 (DOCX 237 kb)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Public HealthChung Shan Medical UniversityTaichungRepublic of China
  2. 2.Department of Infection Control CenterYuan Rung HospitalChanghuaRepublic of China
  3. 3.Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical SciencesTexas A&M UniversityCollege StationUSA
  4. 4.Department of Family and Community MedicineChung Shan Medical University HospitalTaichungRepublic of China

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