Appareil de diagnostic rapide des moisissures sur les matériaux de construction (NOSEMOLD)

Report (2006)

Adaptation de systèmes non-sensoriels de caractérisation d'odeurs à la mesure sur site de la pollution olfactive : Utilisation de capteurs sensibles aux gaz

Doctoral thesis (2006)

Estimation of odor emission rate from landfill areas using the sniffing team method

in Waste Management (2006), 26(11), 1259-1269

The monitoring of the odor annoyance generated by a landfill area is difficult, since it is a multi-area-sources problem, with a discontinuous odor emission. This paper proposes an adaptation of the ... [more ▼]

The monitoring of the odor annoyance generated by a landfill area is difficult, since it is a multi-area-sources problem, with a discontinuous odor emission. This paper proposes an adaptation of the method of sniffing team campaigns to the particular case of fresh waste odors. The method is based on the field determination of odor perception points, followed by data processing with a bi-Gaussian-type model, adapted to handle the odors. In a first step, field observers delineate the region in which odor impact is experienced and then the emission rate is manipulated in a dispersion model until the predicted size of the impact zone matches that observed in the field. In a second step the adjusted emission rate is entered into the model to calculate the percentiles corresponding to the average annoyance zone. The originality of the proposed method is the introduction of all observation points and of all recorded meteorological data into the model. The paper discusses the method limitations and the errors induced on the results, i.e. the odor emission rate and the percentile lines (or iso-concentration lines) which are used to describe the odor concentrations on a map of the surroundings of the plant.The proposed method proves to be reliable for diffuse sources, such as landfill areas. The obtained results are coherent with other results found in the literature with other techniques. [less ▲]

Monitoring the exhaust air of a compost pile as a process variable with an e-nose

in Sensors and actuators. B, Chemical (2005), 106(1), 29-35

In this paper, the monitoring of the composting process with an e-nose is presented. An emission chamber is developed for this purpose and put on a household waste compost pile. A lab-made e-nose with ... [more ▼]

In this paper, the monitoring of the composting process with an e-nose is presented. An emission chamber is developed for this purpose and put on a household waste compost pile. A lab-made e-nose with metal oxide sensors is located at the exit of this chamber. Simultaneously to the e-nose measurements, air sampling on sorbent tubes as well as physico-chemical analysis are realised. The adsorbed air samples are analysed in the lab by gas chromatography coupled to mass spectrometry (GC-MS). In addition, some parameters of the composting process are collected (compost temperature, age of the pile, date of the aeration). Correlation between the sensors and 14 chemical families is determined by principal component analysis (PCA). By canonical analysis, two models are developed and calibrated by the proportion of each chemical family and in function of the compost process events. Thanks to these models, monitoring of various kinds of compost process events is possible with only one measurement device. © 2004 Elsevier B.V. All rights reserved. [less ▲]

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

in Building and Environment (2005), 40(6), 824-831

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 ... [more ▼]

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. [less ▲]

e-nose for malodour monitoring

Poster (2004, March 21)

Establishing the limit of detection and the resolution limits of odorous sources in the environment for an array of metal oxide gas sensors

in Sensors and actuators. B, Chemical (2004), 99(2-3), 384-392

Odour identification with gas sensor arrays relies on two main parameters: the limit of detection, defined as the concentration of the analyte corresponding to the lowest detectable signal for the sensors ... [more ▼]

Odour identification with gas sensor arrays relies on two main parameters: the limit of detection, defined as the concentration of the analyte corresponding to the lowest detectable signal for the sensors, and the limit of resolution, defined for pair-wise comparisons of vapours, as the concentration levels below which a vapour can no longer be reliably recognised from another one on the basis of its response pattern. For real-life environmental odours, however, it is no longer possible to express such limits in "concentration" terms, because they are complex gas mixtures composed of hundreds of various compounds. The paper tries to assess both limits for odorous sources in the environment firstly by finding an equivalence of the odour concentration, expressed in odorous unit per cubic meter (ou/m3), and the concentration of a reference gas, here the ethanol, and secondly by working with a statistical metric, based on the magnitude and standard deviations along linear projections of clustered response data. The methodology is illustrated for a metal oxide gas sensor array and the odour generated by urban waste composting facilities, which is compared to the background air and to ethanol vapour. [less ▲]

Adaptation et test d'un nez électronique pour suivre en continu la nuisance olfactive générée par un centre de compostage

in Revue scientifique des instituts supérieurs industriels libres francophones (2004), 18

L'article présente le travail de fin d'études de Catherine Ledent. Celui-ci a consisté à la mise au point et au test sur le terrain (sur le centre de compostage à Habay) d'un nez électronique destiné à ... [more ▼]

L'article présente le travail de fin d'études de Catherine Ledent. Celui-ci a consisté à la mise au point et au test sur le terrain (sur le centre de compostage à Habay) d'un nez électronique destiné à être placé en continu sur un site industriel, de manière à détecter des occurrences d'odeur. Le prototype existant a été adapté de manière à satisfaire aux exigences du terrain. Par exemple, une régulation thermique de la chambre des capteurs a permis de s'affranchir des variations de température de l'ambiance. La phase de validation sur le terrain fut la plus exigeante: elle nécessitait en effet une présence constante de l'étudiante sur le terrain, de manière à identifier les causes possibles de variation des capteurs. En finale, le système a montré d'excellentes performances et peut servir de base à un développement technologique ultérieur. [less ▲]

Analyse physico-chimique des odeurs de la stations d'épuration d'Arlon

Report (2003)

The use of sensor arrays for environmental monitoring: interests and limitations

in J. Environ. Monit. (2003), 5(6), 852-860

Continuous, in situ monitoring of air, water and land quality is fundamental to most environmental applications. Low cost and non-invasive chemical sensor arrays provide a suitable technique for in situ ... [more ▼]

Continuous, in situ monitoring of air, water and land quality is fundamental to most environmental applications. Low cost and non-invasive chemical sensor arrays provide a suitable technique for in situ monitoring. Their ability and performance under realistic conditions is discussed in this paper. Published studies report promising results despite a number of limitations that are associated with both the technology itself and its application in ever changing ambient conditions. Early investigations include the analysis of single substances as well as odour and wastewater organic load monitoring. Reported applications typically highlight the sensitivity of the currently available sensors to changes in temperature, humidity and flow rate. Two types of approaches are recommended to deal with these effects: either working under fixed experimental conditions or measuring the external parameters to numerically compensate for their change. The main challenge associated with the use of non-specific sensor arrays lies in establishing a relationship between the measured multivariate signals and the standards metrics that are traditionally used for quality assessment of gas mixtures. For instance, odour monitoring requires calibration against olfactometric measurements while investigations of wastewater samples still need to be correlated with organic pollution parameters such as BOD, COD or TOC. On the other hand, results obtained in the field have demonstrated how sensor arrays can be readily used as simple alarm devices or as early warning systems based on a general air/water quality index. [less ▲]