NOVELTY - A carbon monoxide sensor comprises a sensing element; a flow sensor for sensing a flow rate of gas towards the sensing element; and a signal processing module in communication with the flow sensor and the sensing element.    USE - The sensor is used for detecting the presence of carbon monoxide, in the monitoring of heating installations that employ fossil fuels as an energy source and in the monitoring of exhaust fumes from internal combustion engines. It can also be used in self-cleaning ovens and for monitoring the concentration of carbon monoxide in the hydrogen-containing fuel fed to the anodes of a fuel cell.    ADVANTAGE - The invention is a low-cost, fast-response and high-sensitivity carbon monoxide sensor.    DETAILED DESCRIPTION - A carbon monoxide sensor comprises (a) a sensing element (12); (b) a flow sensor (18) for sensing a flow rate of gas towards the sensing element; and (c) a signal processing module (22) in communication with the flow sensor and the sensing element. The sensing element comprises a catalyst dispersed over a metal oxide layer (15). The catalyst is capable of adsorbing carbon monoxide onto the metal oxide layer. The flow sensor sends a signal indicative of the flow rate to the processing module. The sensing element sends a signal indicative of the temperature of the sensing element to the processing module. The processing module measures the carbon monoxide in accordance with the flow signal and the temperature signal.    An INDEPENDENT CLAIM is included for a method of detecting a presence of carbon monoxide in an exhaust stream comprising:    (1) exposing a catalyst dispersed onto a metal oxide layer to the exhaust stream;    (2) adsorbing a portion of the carbon monoxide in the exhaust stream onto the metal oxide layer;    (3) heating the catalyst and metal oxide layer to a first temperature that is as high as the oxidation temperature of carbon monoxide adsorbed onto the first metal oxide layer, thus resulting in an exothermic oxidation of the carbon monoxide adsorbed onto the metal oxide layer and an increase in temperature of the metal oxide layer;and    (4) using the temperature increase of the metal oxide layer, thus indicating the presence of carbon monoxide in the gas.    DESCRIPTION OF DRAWING(S) - The figures show (i) a schematic illustration of a carbon monoxide sensor and (ii) the equation as referenced in the abstract.    Sensing element (12)    Metal oxide layer (15)    Heater (16)    Flow sensor (18)    Filter (20)    Signal processing module (22)