Pollutant sensors; air quality sensors; odor sensors; sensors for detecting gas concentrations and particulate matter; NDIR gas sensors; carbon monoxide sensors; sensors for measuring hydrogen sulfide gas; ozone sensors; metal oxide gas sensors; nitric oxide gas sensors; nitrogen dioxide gas sensors; photoionization (PID) sensors; sulfur dioxide gas sensors; electrochemical gas sensors; electronic circuit boards; electrodes; oxygen sensors, not for medical use; CO2, toxic and flammable gas sensors; dust and particulate emission sensors; gas sensors for measuring gas concentration; pellistor sensors; optical particle counters (OPCs); gas sensor support circuit boards; volatile organic compound (VOC) sensors; sensors for detecting mineral gases; solid phase gas sensors; chemical gas sensors; physical sensors; miniature gas sensors; personal health sensors; smart gas sensors; connected sensors; sensors for internet of things; sensors with data correction algorithms; sensor modules; integrated physical sensors; integrated gas sensors; resistive gas sensors; pollution sensor; safety sensors; process control sensors; combustible gas sensors; covers for gas sensors; gas sensors enclosures; gas sensor instruments and parts; amperometric sensors; galvanic sensors; analytical instruments; vapour sensors; gas analysers; memory integrated sensors; dual gas sensors; sensors for gas leak detection