Terrorism and military actions pose the ultimate challenge to gas sensing

Purpose - This paper aims to provide a review of the uses of gas sensors to detect explosives' vapours and chemical warfare agents (CWAs). Design/methodology/approach - Following a brief introduction, this paper first considers the use of gas sensors to detect explosives. Second, gas sensors that respond to CWAs are discussed. Some mentioned is made of commercial devices but the emphasis is on emerging technologies and recent research. Findings - Detecting explosives is an emerging application for gas sensors. Despite some commercial products, it is the topic of a major research effort and poses a significant technological challenge due to the very low vapour concentrations involved. Many optical and solid-state techniques are under development and some have shown ppt levels of resolution to TNT and allied compounds. Detecting CWAs is a far more mature application and many products exist, often based on analytical methods. Nevertheless, research into improved sensing techniques continues, frequently aimed at detecting ppb concentrations of nerve agents. Much of this research is aimed at meeting the needs of, and is being funded by, the US military and security agencies. Originality/value - This paper provides a technical review of recent developments in the use of gas sensors to detect explosives and CWAs.