Study of highly sensitive smell sensing system using gas detector tube combined with optical sensor

We describe a rapid and low-cost system for monitoring bad smells in the living environment. This system consists of a conventional gas detector tube and an A4-size optical scanner. It was found that methyl mercaptan, hydrogen sulfide and propionaldehyde with the concentrations down to 29 ppb, 19 ppb and 46 ppb, respectively, were detectable. The sensitivity increased by 10 times as large as that of the conventional detector tube utilizing the accumulation effect. Moreover, we have developed a portable sensor using a one-dimensional CCD image sensor. The distribution of bad smell inside the wind tunnel was monitored using multiple portable sensors. The change of the plume shape was clearly observed using the bad-smell sensor network.