If it was H2s, you’d be dead the second that your nose registered the smell of rotten eggs.
No...if you smell H2S it’s a good thing. Once the concentration gets very high (enough to kill you) you will not be able to smell it.
It’s funny that this happened today...I was actually testing an H2S air quality analyzer in Lompoc, CA and I have a cylinder of 50 ppm H2S to test it. It smells BAD!
Unfortunately, The SCAQMD do not outfit any of their air quality sites with H2S air quality analyzers. If they did, we would be able to see activity (if it were H2S).
Not so.
Minimum perceptible odor concentrations are as low as .005 ppm, at 4 ppm the odor is easily detectable, 10 ppm and the eyes start to get irritated, 27 ppm and the odor is strong, 100ppm and the eyes and respiratory tract are noticeably irritated (and the sense of smell paralyzed--you stop smelling it, even if the concentration increases). At 250 ppm prolonged exposure may cause pulmonary edema, and at 500 ppm dizziness and cessation of breathing in a few minutes.
Rapid unconsciousness happens at 700 ppm, almost immediate collapse and respiratory paralysis at 1000 ppm, and 5000 ppm and above you are down for the dirtnap if you aren't very promptly removed from the source of exposure and resuscitated.
It is nothing to mess around with (those poison gas signs are there for a reason around oil well sites), but it won't kill you as soon as you smell it unless you blundered into a high concentration (a twentieth to a half a percent or more in air).