The present disclosure relates to a device for monitoring asthma severity. The available device for monitoring asthma severity is bulky, which makes it difficult to carry around and to transfer from one subject to another. The present invention provides a device for monitoring asthma severity comprising a carbon dioxide (CO2) acquisitions unit, said CO2 acquisitions unit having at least a CO2 nasal cannula unit, a water trap unit, a pump unit, a motor unit and a CO2 sensor unit; a controller module electrically connected to said CO2 acquisition unit, said controller module is an Arduino board having a port connectable to a computer and/or a power unit; a data logging unit electrically connected to said controller module, said data logging unit is a thin film transistor display unit; a real-time control module unit electrically connected to said controller module and said data logging unit; characterized in that said device having at least a user operable switch and an LED; and said data logging unit having a size of 8 cm to 9 cm diagonally. Furthermore, the standard features EtCO2, RR and ICO2 along with specific features such as HA, Area were incorporated for discriminating asthma severity condition and Turns Count algorithm was applied in order to differentiate asthma severity level based on the fixed threshold.