Outputs of Plural Tin Oxide Gas Sensors for Compound Gaseous Indoor-air Pollutants

Abstract

Output patterns of four types of tin oxide gas sensors for compound gaseous indoor air-pollutants are investigated. The sensor patterns prefer higher gas-sensitivity characteristics when there is a compound gaseous pollutant including two kinds of gases. After the experimental system detects a lower gas-sensitivity pattern in a residence, it can detect a higher one. The reverse is impossible. Three NDVs (NDVA, NDVC, NDVN) characteristics are also adopted to increase the reliability of the system. NDVA characterisitic decreases for a few minutes and gets back to an original state or under the state when an alcoholic gas generates. The system can identify whether the alcoholic gas is generating or not in an indoor environment by using NDV characteristics with high reliability.