NOVELTY - The ambient-temperature gas sensor (100) for detecting a variety of specific gases over a range of concentrations, comprises microfabricated interdigitated electrodes (105) formed on a substrate (110) and adapted to be operatively connected to a meter (115) to measure an electrical characteristic between the electrodes, nanostructures (44) in contact with the electrodes, nanoparticles deposited on the nanostructures, and a housing. The sensor is operative at a temperature of 0-200 degrees C. The nanostructures are multi-walled carbon nanotubes. The nanoparticles are less than 10 nm in diameter.    USE - The ambient-temperature gas sensor is useful for detecting a variety of specific gases over a range of concentrations.    ADVANTAGE - The ambient-temperature gas sensor is sensitive to a number of toxic gasses and flammable gasses including hydrogen, nitric oxide, carbon monoxide, ammonia, hydrogen sulfide and methane, can be easily fabricated, and consumes less power.    DETAILED DESCRIPTION - The ambient-temperature gas sensor (100) for detecting a variety of specific gases over a range of concentrations, comprises microfabricated interdigitated electrodes (105) formed on a substrate (110) and adapted to be operatively connected to a meter (115) to measure an electrical characteristic between the electrodes, nanostructures (44) in contact with the electrodes, nanoparticles deposited on the nanostructures, and a housing. The sensor is operative at a temperature of 0-200 degrees C. The nanostructures are multi-walled carbon nanotubes. The nanoparticles are less than 10 nm in diameter. The housing has sidewalls for gaseous communication between an ambient environment and the sensor. The sensor is formed as a semiconductor microchip.    INDEPENDENT CLAIMS are included for:    (1) an array;    (2) a method of detecting a gas; and    (3) a method of making an ambient-temperature gas sensor.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic representation of an ambient-temperature gas sensor.    Nanostructures (44)    Gas sensor (100)    Electrodes (105)    Substrate (110)    Meter. (115)