Improving carbon monoxide (CO) sensors
adapting to environment conditions in Vietnam
Assoc.Prof. Tăng Tấn Chiến, Dr. Bùi Thị Minh Tú
GATEC
Carbon monoxide (CO) is a toxic gas, colorless and odorless. CO obstructs blood delivering oxygen to other parts of the body, including the heart and brain. When victims inhale CO, CO combines with hemoglobin into carbonoxyhemoglobine. As a result, hemoglobin, which has the function of delivering oxygen to the body organs, disappears in the blood.
With a small amount of CO in the air, it may cause nausea, headache and fatigue of the victims. Increasing of CO concentration in the environment causes a serious impact on the victims’ health and leads to death. The presence of CO in the air makes very difficult to detect and to diagnose CO intoxicated victims, leading to a rapid death. Therefore, we call CO “a silent murder culprit”.
CO is produced by incomplete combustion of carbon containing fuels. The higher concentration of the combustion mixture is, the higher is CO concentration in the exhaust gas. Serious consequences occur when exhaust gases of combustion can not escape from closed houses. CO content reaches a dangerous level in the places such as huge furnaces, boiler areas, metallurgy, oil refinery, engine generators, and indoor parking … So the installation of CO sensors in the residential or working places with high risk of becoming affected is extremely necessary. On the market today it can be found three types of CO sensors operating on optical, electrochemical and semiconducting principles. These types of sensors are very sensitive to the environment humidity; therefore they often lose their effect in a short time of using in tropical countries. This makes multiplied increase of CO dangerous level because the user “incorrectly believe” on the CO alarm devices! On the other hand, the more sensitive sensors are, the more easily are affected by changes in the voltage source. In our country, sometimes grid voltage is not stable, making CO alarm tools go wrong or the system does not recognize CO levels causing wrong alarms. So in the scope of this article, we resent the plan to overcome the obstacles mentioned above for the semiconductor – typed CO sensors.
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