Portable device and method for measuring gas in closed space

A method of measuring gas in a closed space using a portable gas measuring device, the method comprising:

• activating the portable gas measuring device according to an event signal;
• supplying power to an oxygen (O2) sensor, a carbon monoxide (CO) sensor, a hydrogen sulfide (H2S) sensor, a hydrogen (H2) sensor, and an air pump to measure a concentration of gas to be measured that is included in air suctioned by the air pump;
• determining whether a concentration of hydrogen gas measured by the hydrogen sensor exceeds a reference value;
• stopping the supply of power to the oxygen sensor, the carbon monoxide sensor, the hydrogen sulfide sensor, the hydrogen sensor, and the air pump when the concentration of the hydrogen gas does not exceed the reference value;
• and
• supplying power to a communication unit and transmitting measurement information to a host system through the communication unit.