Hi Jan-Peter,
I have the Model A and it does not have the VOC (Volatile Organic Compound: https://en.wikipedia.org/wiki/Volatile_organic_compound) option, but other models do (shown in colorful circles on the map in screen shot below). My take is that while some of us do not have all the available sensors, the map choices reflect all of them so we can all see the data of those who do have multiple sensors in their units.
