Pellet sensor based asthma detection system using exhaled breath analysis

Human breath is largely composed of oxygen, carbon dioxide, water vapor, nitrogen and numerous compounds in trace concentration. Exhaled Breath analysis is non-invasive, real-time and low cost technique which can be applied in medicine field both as a diagnostic tool and as a way to monitor the progress of therapies. This paper proposes a pellet sensor which responds to the exposure of exhaled breath. A proportion of zinc oxide and tin oxide nanopowder was used to fabricate gas sensor in the form of pellet. The pellet sensor response for asthmatic exhaled breath varies from normal exhaled breath response. The electrical conductivity, sensitivity, response time and recovery time of pellet sensor with asthmatic exhaled breath exposure has been studied and compared to the normal response. As a part of standard data collection, a spirometer apparatus for differentiating normal person and asthmatic patient is used. The response of pellet sensor is different for normal and asthmatic subjects with stable and repeated response. Characterization of pellet sensor is done for both normal and diseased case. The comparison between normal and asthmatic pellet sensor response can be used as an assistive tool for asthma disease detection.