Abstract <p>The sensory properties of h-Co_<i>x</i>WO₃ (0 ≤ <i>x</i> ≤ 0.09) and h-W_{1 –} _<i>x</i>Fe_<i>x</i>O₃ (0 ≤ <i>x</i> ≤ 0.06) solid solutions, as well as m-WO₃, have been studied in relation to various toxic gases at the maximum permissible concentrations in the air. Doping h-WO₃ with Co²⁺ or Fe³⁺ ions does not affect the sensitivity of the sensory response to CH₃COCH₃ and NH₃ but leads to a decrease in the sensory signal towards NO₂. A comparative analysis of the sensory properties of hexagonal and monoclinic tungsten trioxide has been performed. When detecting CH₃COCH₃ and NH₃, the sensitivity of h-WO₃ is, respectively, ~1.5 and ~1.3 times higher than that of m-WO₃. The oxygen vacancy concentration and pore volume are the key parameters responsible for the higher sensitivity of m-WO₃ to NO₂ compared to h-WO₃.</p>