The present invention is notably directed to a resistive metal oxide gas sensor. The sensor notably comprises a support structure and a patch of sensing material arranged on the support structure or partly housed therein. The patch comprises a metal oxide material. Electrodes are in electrical communication with the patch. The sensor further comprises a heater, in thermal communication with the patch, and a selective gas-permeable filter. The selective gas-permeable filter comprises a fluoropolymer. A first part of an external surface of the patch covers a part of the support structure, while a remaining part of said external surface is coated by the selective gas-permeable filter, so as to form a coated patch of sensing material. The present invention is further directed to related devices and methods of operation.