Microorganisms Improve Indoor Air Quality

Indoor air pollution poses many health threats and comport problems to human life. Because of this, methods to improve indoor air quality are continuously being sought. The purpose of this study was to investigate a novel technology that aims to construct an indoor self-cleaning ecosystem by using microorganisms, namely Bacillus species. The strains used in this technology are Bacillus subtilis, Bacillus pumilus, Bacillus megaterium, Bacillus amyloliquefaciens and Bacillus licheniformis. Instead of applying conventional cleaning products in indoor spaces, microorganisms are nebulized on surfaces, objects and in the indoor air. The key element of this technology is the bioremediation of air pollutants by the Bacillus species to less hazardous metabolites. Scientific evidence concerning the effectiveness of this novel technology is still lacking. Therefore, a crossover pilot study was carried out in an urban region in Flanders and lasted 3 weeks, namely from 14th December 2015 to 3th January 2016. The microorganisms were nebulized in one office building. Of this building, two offices were included in this study. One office of a well-matched neighbouring office building was included as control. The indoor air quality was assessed by tracking particulate matter, carbon dioxide, aldehydes, polycyclic aromatic hydrocarbons, volatile organic compounds, temperature, relative humidity, ventilation rate, total aerobic colony-forming units, yeasts and moulds. Despite the complexity of the real-life study concerning the large amount of variables, the data obtained in this real-life pilot study indicates that constructing a self-cleaning ecosystem might help in reducing the indoor levels of acetaldehyde, particulate matter and total amount of hydrocarbons. The percentage decreases of acetaldehyde and particulate matter concentrations were respectively up to 1.5 and 4 times larger in the offices equipped with a self-cleaning ecosystem than in the control office (P<0.05). Furthermore, this preliminary study showed the feasibility of investigating the impact of bioremediation on indoor air quality and indicated that further research still needs to be done with the aim of validating this innovative technology.


Jelle Verdonck (1)
Katrien Poels (1)
Peter Hoet (1)
Jeroen Vanoirbeeck (1)
Lode Godderis (1,2)


Laboratory for Occupational and Environmental Hygiene, Catholic University of Leuven (1)
IDEWE, External Service for Prevention and Protection at Work, Leuven (2)

Presenting author

Jelle Verdonck, Laboratory technologist, Laboratory for Occupational and Environmental Hygiene, Catholic University of Leuven
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