Microbial volatile organic compounds as indicators of fungi. Can an electronic nose detect fungi in indoor environments?

peer reviewedThe paper presents a review of several studies on the detection of microbial volatile organic compounds (MVOCs) considered as indicators of fungal contamination. As fungi produce specific profiles, or fingerprints of volatile compounds, the electronic nose technology is a very promising opportunity for rapid and non costly detection of fungi in buildings. E-noses are able to distinguish between mouldy and non-mouldy samples, and also to recognise certain species of fungi. However, two limiting factors may appear decisive for employment of electronic noses in indoor fungi detection: low concentrations of MVOCs and presence of interfering substances in indoor environments

Fuzzy K-NN applied to moulds detection

peer reviewedThe possibility to detect Aspergillus versicolor growing on different building materials by a metal oxide sensor array is studied. Results show that an accurate classification rate of 89 +/- 3% can be obtained combining an extended linear discriminant analysis plus a fuzzy k-NN classifier. The classification ability of the classifier is assessed within the dataset by crossvalidation and also in a second dataset collected 5 months later. There is a slight decrease in the classification performance for all the algorithms, being the most sensitive the most accurate one

Les pollutions dans l'air intérieur des bâtiments - Diagnostic - Incidences sur la santé.

Ce n’est qu’au cours des années 70 que certains problèmes de santé ont pu être directement associés à l’environnement intérieur des maisons. Les crises pétrolières ont stimulé une réduction de la consommation d’énergie, entraînant le renforcement de l'isolation thermique des maisons et une réduction de leur ventilation. Si l'objectif énergétique est atteint, il faut constater à présent que la plupart de ces actions ont provoqué l'augmentation des concentrations de certains polluants à l’intérieur des maisons. Cette problématique, généralement connue sous l'appellation "Indoor Pollution", a fait l'objet de nombreuses études et publications. Mais pour améliorer la situation, il ne suffit pas d'inventorier, voire d'étudier les effets possibles des polluants sur la santé, encore faut-il prendre les mesures nécessaires pour remédier au problème. Le présent ouvrage tente de couvrir l'ensemble de la question. Il constitue le résultat d'une recherche bibliographique de publications européennes et mondiales traitant du sujet, de travaux de chercheurs et d’étudiants de la F.U.L., de contacts avec les institutions et organisations s'occupant de la pollution intérieure ainsi que d’expériences personnelles dans ce domaine. Il est le fruit d'une réflexion commune entre la Province de Luxembourg et la F.U.L., dans l'esprit de la mise en place de services d'intervention en matière de pollution intérieure. Il s'adresse donc essentiellement à tous les professionnels qui, de près ou de loin, sont concernés par la question. En une bonne centaine de pages, le livre reprend synthétiquement chacun des principaux polluants communément rencontrés dans les maisons, et plus particulièrement en Belgique. Il en identifie les sources et les effets sur la santé, ainsi que la réglementation les concernant et un certain nombre de conseils pratiques. Par rapport à l'information généralement disponible dans d'autres ouvrages, celui-ci ajoute les méthodes d’analyses de référence ainsi que les techniques alternatives de détection de chaque polluant. Un accent tout particulier à été mis sur les méthodes optimales de terrain à mettre en place par un service de conseil d’analyse de l’air dans les bâtiments. Cette publication, originale par son caractère pratique et complet, doit intéresser un grand nombre de personnes concernées par la problématique de la pollution intérieure : les scientifiques, les médecins, les laboratoires, les pouvoirs publics, et en particulier les responsables et les travailleurs des services d’intervention en matière de pollutions intérieures, les services de sécurité et d’hygiène, etc

First step to build on index to detect microbial volatile organic compounds emitted by moulds growing on building materials.

peer reviewedNowadays, the detection of moulds hidden in buildings is only possible after degradation of the building materials. In the early 2000s, a new approach is suggested to detect fungal contamination of building materials. This one is based on the determination of the VOC emitted by the mouds, called Microbial-VOC (MVOC). This study was conducted to screen the emission of MVOCs by three different moulds growing on specific materials (shower mat, plasterboard, wood wool). The carbon dioxide, as indicator of biological activity, was also measured. In this paper, the development of an integrated index was considered for a new approach in the detection of hidden moulds. The index will be an algorithm with various variables specific to the moulds (for example : RH, CO2, single VOC and specific VOC pattern...). The goal is to propose an innovative and simple tool working with low cost sensors

Development of an instrument to evaluate the impact of moulds-sensitive materials on indoor air quality

In the frame of a FIRST-Europe project, the research team worked with a partner from university of Barcelona (Spain) and a company fabricating products to reduce moisture problems in dwellings. An original instrument was designed. It was based on the "electronic nose" principle. With suitable data processing tools and an adequate calibration, the instrument was able to distinguish, from the analysis of the gas phase, the emission of the clean material from the one of the same material contaminated by moulds and from the one of the product against humidity. Discriminating between different mould species was more difficult.Développement d'un instrument d'évaluation des impacts de matériaux sensibles aux moisissures sur la qualité de l'air intérieur

Détection des moisissures de l'habitat par un nez électronique

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The electronic nose : a tool for controlling the industrial odour emission. Application to the compost processing

peer reviewedDifferent laboratory-made electronic noses, based on commercial tin oxide gas sensors were used to identify typical sources of odour nuisance : printing houses, paint shop in a coachbuilding, wastewater treatment plant, urban waste composting facilities or rendering plant. All the samples were collected in the field from real malodours in uncontrollable conditions. In spite of the influence of environmental parameters, results demonstrated the ability of such simple systems to detect and identify typical odour nuisances. Those findings encouraged us to develop portable instruments able to monitor continuously the odours emerging from factories or from landfills sites. The paper analyses the type of output signal most adapted both to detect the rise of a particular odour in the background and to monitor it continuously, in order to allow a decision making in real time. The method is illustrated on a particular application : the monitoring of the odour generated by a municipal waste composting process. The paper discusses the ability of a technique based on an electronic nose to control the odour abatement device, which is the atomisation of a neutralising agent. To reach such final goal, the main difficulties to overcome are : - to cope with the sensor drift - to lower the limit of detection and the limit of recognition of the sensor array - to improve the reproducibility of the sensors. However, comparing the sensor array signals with analytical and olfactometric results leads to promising conclusions regarding two main possible applications : - using the odour, as detected by the electronic nose, as a process variable for the compost formation; - predicting the raise of malodour in the background before it becomes an annoyance for the surrounding

Product policy in the context of the indoor environmental quality

A. Context One of the objectives of the European Construction Products Directive (CPD) is to harmonize the technical specifications with regard to dangerous substances and construction materials. Construction products could emit or contain dangerous substances that have been defined as dangerous substances under Commission directives and national regulations. In the future construction products may only be placed on the market in the European Union if they accord with the (second generation) harmonized technical specifications including health aspects and bear the CE mark. B. Objectives The goal of this research project is to improve the flow of knowledge and information vis-à-vis normalisation activities in the domain of indoor air measurements, indoor product emission testing, labeling and certification by proposing an evaluation method and standardized assessment methods for a harmonized approach relating to emissions from building materials into indoor air for implementation in Belgium. This approach will comply with current European harmonizing efforts ongoing on European level. C. Conclusions International tendencies as well as national developments indicate the growing importance of building material emission testing Harmonisation of governmental schemes to assess volatile organic emissions in the context of the CPD is necessary to obtain transparency The topic of different limit values in different countries is a difficult problem to solve It was demonstrated that it is possible with alternative methods (µ-chamber and FLEC) to achieve a qualitative and quantitative correlation with the reference method. However there is a need to extend this comparative study to more materials The important influence of the quantification procedure on the emission results was demonstrated The possiblity to investigate microbial resistance of building materials with the so called µ-chamber technique was demonstrated A twofold methodology for the odour determination of building materials was developed: a quantitative method based on intensity and a qualitative method based on hedonic scale. Furthermore the basis for the development of an electronic nose specific for evaluation of building materials was laid down A possible evaluation scheme for Belgium on the basis of AFSSET/AgBB/prEN15052 was proposed with two modifications: - Time path modification (7 or 10 days) - Prescreening with alternative method (< 20 L) D. Contribution of the project in a context of scientific support to transfer of knowledge and innovation This research project for implementation of the essential requirement “Hygiene, health and the environment” of the Construction Products Directive has besides its informative and sensitizing role also performed a supporting role in the development of new innovative low emission construction products. The research project has also ensured a Belgian input in the validation work of the draft standard "Emissions into indoor air" - WI 351009 - Construction products - Assessment of emissions of regulated dangerous substances from construction products - Determination of emissions into indoor air” in development in working group 2 of CEN/TC 351. Furthermore this research project has lead to the development of new innovative test methods tailored to the specific needs of construction products

Status: Postprint (Author’s version) Microbial volatile organic compounds as indicators of fungi. Can an electronic nose detect fungi in indoor environments?

Abstract: The paper presents a review of several studies on the detection of microbial volatile organic compounds (MVOCs) considered as indicators of fungal contamination. As fungi produce specific profiles, or fingerprints of volatile compounds, the electronic nose technology is a very promising opportunity for rapid and non costly detection of fungi in buildings. E-noses are able to distinguish between mouldy and non-mouldy samples, and also to recognise certain species of fungi. However, two limiting factors may appear decisive for employment of electronic noses in indoor fungi detection: low concentrations of MVOCs and presence of interfering substances in indoor environments

Detection of moulds growing on building materials by gas sensor arrays and pattern recognition

peer reviewedThis work explores the detection of moulds growing in different building materials by using a metal oxide sensor array Four mould species have been considered. Pattern Classification provides classification rates on the order of 80-90% for different species. Drift degrades slightyl these values subsequent test four months later