Risks of unsatisfactory airborne bacteria level in air-conditioned offices of subtropical climates

Research output: Journal article publicationJournal articleAcademic researchpeer-review

28 Citations (Scopus)


Adjustment of the indoor air temperature and relative humidity set points for energy conservation is adopted in many air-conditioned offices in the subtropics. This study examines the environmental risks in an air-conditioned office with a 'readjusted' thermal environment from the perspective of the probable airborne bacteria level exceeding certain limits. In particular, a cross-sectional study of bacteria concentrations in 422 air-conditioned offices in Hong Kong was conducted, and a mathematical expression was proposed to correlate the indoor bacteria level with the indoor air temperature and relative humidity in an air-conditioned office. With the proposed correlation, the probability of an air-conditioned office having an unsatisfactory airborne bacteria level could be determined. The model results were verified with the measurement results from some other studies. This model would be a useful tool for preliminary assessment of the environmental risks, regarding the airborne bacteria level while balancing some energy conservation measures, in an air-conditioned office in the subtropics. The study also provides a template for developing an environmental risk assessment model in air-conditioned spaces elsewhere.
Original languageEnglish
Pages (from-to)475-479
Number of pages5
JournalBuilding and Environment
Issue number4
Publication statusPublished - 1 Apr 2008


  • Air-conditioned offices
  • Airborne bacteria level
  • Humidity
  • Temperature

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Environmental Engineering
  • Geography, Planning and Development

Cite this