Non-injective gas sensors contain fewer MOFs than degrees of freedom in the gas composition. They are vulnerable to blindness: the sensor is unresponsive to certain gas composition changes. Our work focuses on identifying these vulnerabilities in non-injective gas sensors. Moreover, the sensor is more sensitive to certain gas composition changes than others (of the same magnitude). We show that the singular value decomposition of the Jacobian matrix of the adsorption function a(x) is key to identifying directions in composition space to which the sensor is most-, least-, and unresponsive.