A toxic gas detector, otherwise known as a toxic gas monitor, is a device that measures and indicates the presence and or concentration of toxic gases found in the air around it. They can be built for use in a fixed position, such as being mounted on a wall, or may be designed as portable devices in order to check for toxic gas in outdoor settings. These detectors provide concentrations of gas in the air using a measurement of parts per million (PPM). This means that there is one part toxic gas per one million parts air that have been measured.
Examples of toxic gases that can be detected by a toxic gas detector include carbon monoxide, chlorine and nitrogen oxide. It is important to keep a check of these gases, as different levels of gases can be tolerated by the human body for different amounts of time. For example, carbon monoxide can be tolerated in the 30 PPM level for eight hours, while 800 PPM can be lethal to the human body if exposed to for even two hours, or less.
There are two main ways to detect toxic gases, through the use of electrochemical sensors or metal oxide semiconductors. An electrochemical toxic gas detector uses electrodes to indicate that a gas has been found in the air. Most detectors contain two to four electrodes, which act as electrical conductors. When the gas enters the toxic gas detector, it reacts with the electrodes and this chemical reaction causes an electric current to be produced. The sensor then measures the current to determine the amount of the gas that is present in the air.
A metal oxide semiconductor is a toxic gas detector that works through the use of a film that reacts to one toxic gas only, such as carbon monoxide or hydrogen sulfide. The film found within this type of detector is usually made from tin oxide or tungsten oxide. The detector measures the reaction of the gas with the metal oxide within it and it is triggered when the particular gas being measured reaches toxic levels within the air.
Toxic gas detectors are important because they can prevent a variety of health problems caused by different gases. They are vital because many of the toxic gases are colorless and do not emit an odor detectable by human senses. This is particularly relevant in the case of long-term exposure, which can cause unconsciousness, brain damage, or even death.