In this work, a novel textile based wearable mask antenna is proposed to detect harmful gases. The antenna is placed on a denim substrate with a size of 44 × 44 × 1.1 mm3. This proposed antenna is a textile based, Microstrip patch antenna (MPA) whose feed is given through Co-planar wave guide (CPW) feeding technique and the ground plane here is considered to be a defected ground structure (DGS). To analyze its purpose of detecting harmful gases, the antenna is simulated using CST Simulation software. Analysis of the antenna parameters was carried out by placing it in a simulated gas chamber. The gases used for testing the antenna here were Carbon monoxide (CO), Butane (C–4H10), and Liquid petroleum gas (LPG). When the designed antenna is placed in a free space it is observed that it resonates at 2.464 GHz (2.32–2.64 GHz) which covers the ISM band with a respective reflection coefficient (S11) of −32.063 dB, gain of 3.45 dB, and radiation pattern in E-plane is bi-directional and H-plane is uni-directional. But when the same antenna with simulated human tissues is placed in a gas chamber containing Carbon monoxide, it resonates at 1.556 GHz with S11 value of −18.86 dB and gain of −6.810 dB. It is also observed that, in the case of Butane gas the operating frequency of the antenna shifted to 1.5 GHz with S11 value of −22.5 dB and gain −5.87 dB. In the case of LPG the antenna resonates at 1.46 GHz with S11 value −26.04 dB and gain −5.47 dB. The radiation pattern for layered planar antenna in E-plane and H-plane is observed to be uni-directional and semi omni-directional. The SAR value for planar antenna with simulated human tissues is 1.33 W/Kg. With the results and analysis, the proposed antenna is suitable for wearable face mask applications, for the detection of harmful gases.