Odor of Fire

Abstract

Odor perception is the only one of our five senses that reaches beyond time and space. In ancient times odor was used more often in order to discriminate, foreknow and avoid existing danger. However, the modern lifestyle has taken away the original sharpness of our five senses. In this review work, we surveyed the nature and explained the usefulness of the active odor recognition of fire by odor in Melanophila. Odor perception enables creatures to sense the outer world, for example, sniffing the future world of emerging danger and the past world by tracking any trace of bait for their survival. We examined the burn smell of wood as an example of present odor detection. We found that the decomposition products of cellulose and perfumes of the wood are generated when wood is heated and pyrolized, and that levoglucosan is the signal molecule from fire and burning wood. Because of a lack of fossil-fuel energy and carbon dioxide emissions problems, an energy revolution has taken place, and new energy sources, like hydrogen and dimethylether (DME), will be introduced into our life. In this era, no smog and less carbon dioxide is released by fuel, and with less odor. We cannot sniff soldering smell in our daily life, and thus need some new sensor to monitor the combustion system in order to guard our life in such an era. Here, we introduce a semiconductor odor sensor and soft ionization mass spectrometry as a "smart nose". The odor molecules are encapsulated in the graphite microcapsule structure of soot, which reserves them without release. Recent scientific analysis on soot provides tools for fire research in order to distinguish fire from arson. Furthermore, in our group, hydrogen emission experiments were conducted; the hydrogen concentration was monitored by a new type ion sensor for hydrogen. The real-time performance of this Hydrogen sensor is introduced.