The state or quality of being sulfurous, having the smell or characteristics of sulfur.
Sulfurousnesses might be associated with a bad smell or something that is not good for you.
Examples:
The sulfurousnesses of the hot spring made it unpleasant to be near.
The sulfurousnesses of the volcano filled the air with a bad smell.
I don't like the sulfurousnesses of rotten eggs.
The sulfurousnesses of the swamp made it a stinky place to visit.
The sulfurousnesses of the chemical spill made the air hard to breathe.
The sulfurousnesses of the fireworks filled the night with a strange smell.