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EPA \ TAQMN \ Air Quality Monitoring \ Instrument database \ CO

Carbon Oxide (CO)

Carbon Oxide (CO) analyzer uses the instrument designed with the principle of absorbing non-dispersive infrared. The principle is using the attribute of CO that would absorb the infrared with wavelength of approximately 470 mm. The CO concentration within the air can be found by observing the change of the infrared strength before emission and after reception. Since there is a direct proportion between CO concentration and degree of infrared absorption, the higher of the degree of absorption, the higher the relative CO concentration measured from the air is.

In the beginning of analyzing the sample air, the system will import the air into the sample reaction cell, irradiate it with infrared, and then measure the strength of infrared. There is another sample reaction cell installed next to the previous one as the comparison group. This reaction cell contains zero gas (the gas that would not absorb infrared); that means the measurement of infrared absorption is zero. By comparing the infrared absorption of the two reaction cells, the net absorption degree can be found. Before the sample gas enters the reaction cell, it will pass through a dehumidifier and a filter because the atmosphere contains water and floating solids. These two matters would absorb infrared and interfere with the analysis of CO. They have to be removed so that there will be no interference.


Instruments measured carbon monoxide (CO) concentration process

last update : 2017/07/31

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