Carbon monoxide alarm is used to detect carbon monoxide (CO). It can not be used to detect alkane gas such as methane (CH4). Gas alarms on the market are usually used to detect natural gas, liquefied petroleum gas or coal-based gas, and urban pipeline gas is usually one of the three gases. The main components of these gases are methane (CH4) and other alkane gases, the main feature of which is a pungent odor.
In addition, heating with coal stoves, burning coal and so on produces a carbon monoxide gas (CO), not methane (CH4) and other alkane gases. Therefore, carbon monoxide alarm should be used instead of gas alarm. In short, if you're testing for toxic gases, and you're concerned about whether they're poisoned, then you must use a carbon monoxide alarm. If you want to detect explosive gases, the concern is whether there is leakage in the pipeline, the general use of gas alarm can be.