Gas Sensors

Gases pervade the environment and in an appropriate mix are essential for sustaining life on the planet. The atmosphere naturally contains a large number of gases, albeit some at low concentrations. Human activities, particularly since, and as a result of, the Industrial Revolution, have modified background concentrations and have, as a consequence, had an environmental impact: examples include the greenhouse effect, acid rain and photochemical smog. In some cases, as for example, with an escape of inflammable gas such as methane or the inhalation of a toxic gas such as carbon monoxide, there is an immediate safety hazard to life in the vicinity of the source. Clearly, there is a need for sensors (preferably low-cost) which enable the concentration of gases modified by our activities, or unusual concentrations generated by natural processes, to be quantitatively determined at or close to active plant, appliances or other sources. Furthermore, many processes in industry, in motor vehicles and in domestic appliances involve gaseous chemical or electrochemical processes which require the control of the concentrations of the active species in order to maximise yield or efficiency and minimise pollution. Sensors responsive to the relevant gases and providing a quantitative output are important components of the control systems. There is much work going on in the international community, both in academia and in industry, to develop sensors for what is a wide range of tasks. Some of that work has led to the availability of commercial sensors, while others are still at various stages of development. Often the sensor must operate in a hostile environment and acheiving adequate life at an acceptable price is difficult, requiring the solution of a multitude of interdisciplinary problems. As a result development times to a successful product are often long and are usually measured in years. In this volume, research and development in this diverse and fascinating subject area has been thoroughly reviewed. The aim has been to produce a concise work valuable to both specialists and non-specialists alike. Emphasis has been placed on the underlying principles, normally requiring discussion of the physics and chemistry involved.

Table of Contents:
Electrochemical sensors with liquid electrolyte. Electrochemical sensors with solid electrolyte. Chemoresistive sensors. Calorimetric sensors. Field-effect sensors. Other sensors and developments. Commercial and economic factors.