This article explores potential everyday applications of terahertz gas spectroscopy technology. A breath sensor demonstration detected acetone with an absorption cell to significantly improve the detection limit and a system composed of TX and RX modules based on SiGe BiCMOS technology. This demonstration achieved a measured power of 870 µW at 230 GHz and noise temperatures between 10,000K and 20,000 K, and the same system could be applied to detect other gasses in breath for medical monitoring purposes. Carbon monoxide emission line detection and Lamb-dip detection for methanol may be utilized to realize frequency stability with Alan deviation on the order of 10-11 with this system.