Original Research

The impact of a disinfection intervention on the microbial indoor air quality at a university library

Abstract

Introduction: Indoor environment contributes to human health and productivity. The absence of climatic control systems may lead to microbial contamination. The air quality of public institutions should be monitored.
Therefore, this study was conducted to determine the microbial load of the air in the main library at the University of Guyana and to evaluate the effectiveness of a disinfection intervention on the microbial load of the air.
Materials and methods: This was an experimental- observational study involving three phases: analyzing the microbial quality of the air, a disinfection experiment, and a disinfection intervention. Phase 1 was done before the rehabilitation of the library, Phase 2 was done during the rehabilitation, and Phase 3 was carried out after the rehabilitation and the disinfection intervention. Samples were collected on settle plates and incubated. ColonyForming Units (CFUs) were enumerated and the microbial load was determined using a standardised equation. Several disinfectants were tested against two bacteria and a specific disinfection protocol was developed for the disinfection intervention.
Results: The bacterial load for Phase 1 (13,114 CFU/m3) and Phase 2 (7,636 CFU/m3) was higher than that of Phase 3 (4,648 CFU/m3). There was an extremely high fungal load (4,067 CFU/m3) before the disinfection intervention but no growth after.
Conclusion: We concluded that a high microbial load was found in our study before the disinfection intervention which was considerably diminished after the intervention. We recommend implementing the cleaning regimen we developed as part of the library’s cleaning protocol.

1. Śmiełowska M, Marć M, Zabiegała B. Indoor air quality in public utility environments- a review. Environmental Science and Pollution Research. 2017 Feb 24; 24 (12): 11166–11176.
2. Wamedo SA, Ede PN, Chuku A. Interaction between building design and indoor airborne microbial load in Nigeria. Asian Journal of Biological Sciences. 2012 May 1; 5 (4):183-191.
3. Meadow JF, Altrichter AE, Kembel SW, Kline J, Mhuireach G, Moriyama M, et al. Indoor airborne bacterial communities are influenced by ventilation, occupancy, and outdoor air source. Indoor Air. 2013 May 24; 24 (1): 41–48.
4. Rocchi S. Relationship between Microbiological Profiles of the Indoor Environment and Infectious and Allergic Respiratory Diseases. Human Medicine and Pathology. University of Franche Comte, Besançon. 2014.
5. Jabeen R, Kizhisseri MI, Mayanaik SN, Mohamed MM. Bioaerosols assessment in indoor and outdoor environments: a case study from India. Scientific Reports. 2023 Oct 23; 13 (1): 1-12.
6. DeLeon-Rodriguez N, Lathem TJ, Rodriguez-R LM, Barazesh JM, Anderson BE, Beyersdorf AJ, et al. Microbiome of the Upper Troposphere: Species Composition and Prevalence, Effects of Tropical Storms and Atmospheric Implications. Proceedings of the National Academy of Science. 2013 Jan 28.110 (7): 2575-2580.
7. Mentese S, Mirici NA, Otkun MT, Bakar C, Palaz E, Tasdibi D, et al. Association between respiratory health and indoor air pollution exposure in Canakkale, Turkey.Building and Environment. 2015 Nov 1; 93 (1): 72-83.
8. Dasaraju PV, Liu C. (1996). Infections of the respiratory system. [Internet]. 4th ed. Baron S, editor. Pubmed. Galveston (TX): University of Texas Medical Branch at Galveston; 1996. Available from https://www.ncbi.nlm.nih.gov/books/NBK8142
9. Hayleeyesus SF, Manaye AM. Microbiological Quality of Indoor Air in University Libraries. Asian Pacific Journal of Tropical Biomedicine. 2014 May; 4 (1): 312-317.
10. WHO Guidelines for Indoor Air Quality, Dampness and Mould. WHO Regional Office for Europe. 2009 Jan 1. [Online]. Available from https://www.who.int/publications/i/item/9789289041683
11. Hospodsky D, Qian J, Nazaroff WW, Yamamoto N, Bibby K, Rismani-Yazdi H, et al. Human occupancy as a source of indoor airborne bacteria. PLoS one. 2012 April 18; 7 (4):1-10.
12. Wiszniewska M, Walusiak-Skorupa J, Pannenko I, Draniak M, Palczynski C. Occupational exposure and sensitization to fungi among museum workers. Occupational Medicine.2009 March 26; 59 (4): 237 242.
13. WHO Indoor Air Pollution Habitats and Health. Checklist N°292 Site Consulted. 2016 [Online]. Available from http://www.int/entity/mediacenter(fctsheets/fs292/fr/index.htlm
14. Wood L. Prevention and Treatment of Molds in Library Collections, Especially in Tropical Climates: A RAMP Study. UNESCO. 1988; 56.
15. Ashuro Z, Diriba K, Afework A, Washo GH, Shiferaw A, Kanno GG, et al. Assessment of Microbiological Quality of Indoor Air at Different Hospital Sites of Dilla University: A Cross-Sectional Study. Environmental Health Insights. 2022 Jan 18; 16.
16. Indoor Air Quality and Its Impact on Man. Biological Particles in Indoor Environments, Report No. 12, Commission of the European Communities, Luxembourg. 1993.
17. Dehghani M, Sorooshian A, Nazmara S, Baghani AN, Delikhoon M. Concentration and type of bioaerosols before and after conventional disinfection and sterilization procedures inside hospital operating rooms. Ecotoxicolgy and Environmental Safety. 2018 Nov; 164: 277–282.
18. Rocha CA, Silva RJ, Monzón AE, Alfonzo J. Characterization of Indoor Air Bioaerosols in an Electrical Headquarter Building. Indoor + Built Environment. 2012 Oct 11; 22(6), 910–919.
19. Landry KG, Ascension NM, Armelle DCA, Hortense GK, François-Xavier E. Assessment of Indoor Microbial Quality of Library’s Premise: Case of Central Library of the University of Yaoundé I. Open Journal of Preventive Medicine. 2018 April 25; 8(4):109-120.
20. Adetitun DO, Oladele IL. Air-Borne Microbial Load and Diversity in Some Offices in University of Ilorin. Nigeria Journal of Pure & Applied Science. 2016; 29: 2715-2733.
21. Gilbert JA, Hartmann EM. The indoors microbiome and human health. Nature Reviews Microbiology. 2024 Jul 19.
22. Awad AH, Saeed Y, Hassan Y, Fawzy Y, Osman M. Air microbial quality in certain public buildings, Egypt: A comparative study. Atmospheric Pollution Research. 2018 July 1; 9 (4): 617 – 626.
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IssueVol 10 No 3 (2025): Summer 2025 QRcode
SectionOriginal Research
DOI https://doi.org/10.18502/japh.v10i3.19600
Keywords
Indoor air; Microbial load; Disinfection experiment; Disinfection intervention; Library
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How to Cite
1.
Ally Charles B, Tyrell E, Hohenkirk K, Hutson A, Vanlewin O. The impact of a disinfection intervention on the microbial indoor air quality at a university library. JAPH. 2025;10(3):395-410.