I would like to know what the "air quality sensor" does. A lot of the places I would want an air sensor are locations in the house where many of the other featu

I would like to know what the "air quality sensor" does. A lot of the places I would want an air sensor are locations in the house where many of the other features would be useless and/or unwelcome. The placement/howmany guide suggests that the use case is largely entrances. Entrances are the last place I would want to put a air sensor, thermometer and/or hygrometer.