Aerosol assisted chemical vapour deposition (AACVD) reactions of tungsten hexacarbonyl, [W(CO)₆], in acetone, methanol, acetonitrile and a 50 : 50 mixture of acetone and toluene resulted in the deposition of blue partially reduced WO_3−x films which showed preferred orientation along the (0 1 0) direction. Films deposited solely from toluene, however, were composed of a mixture of tungsten metal and W₃O. All films could be annealed to yellow randomly orientated crystalline monoclinic WO₃. The films deposited from methanol had a morphology comprising of a network of randomly orientated needles, which is strikingly different to the agglomeration of spherical particles observed with the other solvents. The WO₃ films functioned as gas sensitive resistors for the detection of NO₂. Responses were recorded at minimum concentrations of 1.03 ppm of NO₂, significantly exceeding those of commercial screen printed sensors.