Posts tagged "air intérieur"

Communicating electronic nose for indoor air quality control

LAAS/CNRS - LCC/CNRS - Laplace, Toulouse University


E-nose, indoor air quality, multi-gas sensors, nanostructures, metal oxide semiconductors, sensitivity, selectivity, internet of thing (IoT).

Humans spend more than 90% of their time in a closed environment that contains several gaseous pollutants like VOCs (volatile organic compounds). Such gaseous contaminants in the indoor air may cause respiratory problems and chronical diseases. Many others gases such as CO2, CO, and NO2 from urban pollution and poor ventilation systems are also part of indoor air contaminants. Offices, meeting rooms, classrooms and practical workrooms in universities and / or schools may present VOC and /or CO2 levels that exceed the regulatory thresholds. Measuring and monitoring indoor air quality is therefore essential to ensure a better quality life in workspaces. This thesis has been carried out within the framework of the GIS neOCampus (groupement d’intérêt scientifique), led by Université Paul Sabatier UT3 and dedicated to the development of an innovative, connected and sustainable campus for a better quality life. We are interested in the development of miniaturized MOS (metal oxide sensors) gas sensors for the indoor air quality monitoring in offices and classrooms. The objective of this study is to control these pollution levels in order to correct them through measures to ventilate the premises. Making a decision about how to correct air quality is an essential step in the process. As part of this work, we have prepared several prototypes of miniaturized multi-gas sensors (4 sensors) integrated on their electronic card able to detect levels of indoor air pollution. The proximity electronics allows the control and recovery of data from these sensors, and an IOT (internet of things) type communication module based on the WiFi protocol linked to the "Cloud NeoCampus", remotely and wirelessly, generates indoor-air quality signal in real time. This multi-sensor is based on semiconductor sensors based on nanostructured metal oxides (SnO2, WO3, CuO) synthesized at the LCC (laboratoire de chimie de coordination).

Scientific goal

We have developed a new synthetic approach for the nanostructured metal oxides on the sensor platform in order to optimize the performance of the sensitive layer (stability, sensitivity, selectivity). We have studied very efficient associations of n-type and p-type MOS nanostructures based on multilayered implementation on silicon platforms. The gas responses have been measured in laboratories test benches and new measurement protocols (cycled temperature mode versus continuous operation mode) have been defined to selectively detect NO2 or VOCs compounds in air at ppm and sub ppm levels. In addition, PCA (principal components analysis) analyses have been set up to discriminate gas mixtures in test benches.


Embedded Multi Gas Sensors for Indoor Air Quality Monitoring

Context Presentation

The measurement of indoor air quality is important for health protection against chemical and gaseous pollutants ... The indoor air can contain many pollutants such as CO, CO2, NO2 and VOCs. These pollutants exist in different materials and products that can be used in housing (furniture, cleaners ...), but can be also coming from human activities or outside source. In this case, the detection, measurement and monitoring of these gazeuse contaminants is necessary.

In view of its high performance and low cost, the innovative gas multi-sensor based on metal oxides semiconductors for analyzing and controlling indoor air quality is a good alternative to electrochemical and infrared sensors. This project is currently in progress in LAAS in collaboration with the LCC and Laplace and as part of a thesis funded by neOCampus and the Occitanie region.

This thesis focuses on the characterization of multiple MOX-based gas sensors and integrates these multi-sensors in electronic card to achieve a connected object to control the indoor air quality in offices and classrooms in University Paul Sabatier in Toulouse. The gas multi-sensor is a microsystem composed by four sensors on a microchip, realized to detect target gases.  



Multi-sensors, MOS, Indoor Air Quality, Smart Building, neOCampus

Scientific goals

•    To characterize new nanomaterials (SnO2, CuO, ZnO, WO3 ...) designed by the LCC by using an experimental set-up,

•    To define an operating protocol by trying different operating modes.


Sensors and Photocatalytic Coatings for Indoor Air Quality: Detection and Degradation of Pollutants

Context Presentation

We spend around 85% of our time indoors. However, indoor air is 5 to 10 times more polluted than outside air. Based on this observation, various laboratories at the Paul Sabatier - Toulouse III University are focusing part of their research on the development of tools for measuring and improving the Indoor Air Quality.

This is the case of LAAS (Systems Architecture Laboratory), LCC (Coordination Chemistry Laboratory) and LMDC (Materials and Construction Durability Laboratory), which work in collaboration on the development and optimization of MOx gaz sensor (semiconductor metal oxides) to detect different gases in the air (LAAS and LCC), and photocatalytic coatings (LMDC and LCC) to degrade or decrease the concentration of gaseous pollutants.

During this internship, the gases mainly treated are nitrogen oxides (NOx). The aim is to assess the effectiveness of the sensors developed by LAAS and the LCC in detecting variations of NOx concentration and the effectiveness of the coatings in degrading them.

 Image_NeoCampus - Mathieu Delaveau


neOCampus, Indoor Air Quality, Sensors, Photocatalysis, Nitrogen Oxides, Metal Oxides Semiconductor

Scientific goals

•    To integrate the LAAS / LCC gas sensors into the LMDC test device (Figure 1).

•    To compare the detection capacity of the NOx sensors and analyzer currently present at the LMDC.

•    To carry out abatement tests to test the depollution efficiency of various photocatalytic coatings, in particular based on ZnO and TiO2, and compare the results obtained with the two measurement systems (analyzer and sensors).


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