> I read those threads, but I don't have a rotten egg smell, at
least
> not yet. It's more like the smell of a match head and is harsh on
the
> nose. This suggests to me a different sulpher compound than H2S.

A good solid whiff of CO2 will hurt your nose pretty bad. Is is
possible that you experienced this, with just a little H2S mixed in to
give the sulfury impression?

--arne