What are you saying, that because some VOCs are found in nature, any man-made VOC is OK too, just because it is part of the same chemical compound family?

I think the appropriate conclusion would be your sensitive to something more specific than just the very broad class of VOCs in general.

So... the ones I am not sensitive to, are they not harmful?

Just for the record, VOCs are literally "anything organic that boils at less than 250°C" (in the EU).

Farts are full of VOCs. No, seriously, every time I fart the TVOC sensor in my air purifier goes nuts, as does the one in my air quality meter. It's almost like the thing is shaming me for it :)

I would encourage you to learn more about the different types of VOCs, and at which concentrations they are known to be harmful. You might be having true allergic reactions to some harmless VOCs. You might be having psychosomatic reactions to other VOCs. You might not be having reactions to some harmful VOCs at all. Lumping it all together into "VOCs" is not helpful.

Wait a minute, so you're telling me when I was laughing with my husband about how we should fart in front of the new air purifier and see if the sensor went off and he dismissed me, rolled his eyes and called me juvenile THAT I WAS RIGHT ALL ALONG?!?!?

I,m using a more restricted definition of synthetics which we didn,t evolve with.

I don't know that we know enough to know that. It's certainly true that there are "natural" VOC's that can be harmful, and man-made VOC's that are not known to be harmful. I wouldn't necessarily presume that sensitivity is directly correlated to harm.