Testing and Validation of Mobile Air Quality Monitor for Sensing and Delineating VOC Emissions

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Thakor, Govind Singh
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University of Guelph

The uRAD A3 air quality monitor uses a linear model to convert the output resistance value of the metal oxide sensor into air quality index in terms of VOC (AQIVOC). To improve this representation of AQIVOC a predictive algorithm was developed to convert the resistance to concentration values and then to AQIVOC. The A3 monitor was first validated through point source emissions and comparison with an analyzer. Then it was calibrated under controlled conditions for three different types of VOCs – acetone, ethanol and hexane. Experiments were performed for each solvent and in combination to observe how each solvent interacted with metal oxide sensor to understand the relationship between the resistance and concentration through analysis. Resistance range of each solvent (acetone - 15.24 to 8.5 Kohms, ethanol - 25.73 to 13.59 Kohms, hexane - 104.25 to 43.49 Kohms) and resistance-concentration relationship served as the basis for algorithm development for predicting total concentration of VOCs and their individual composition

Air Quality Index, Predictive Algorithm, Metal Oxide Sensor, VOCs, Resistance-Concentration Relationship, Air Quality Monitor