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Author: Subject: olfactory fatigue
alive&kickin
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[*] posted on 5-12-2015 at 06:24
olfactory fatigue


Looking for some information and coming up blank. Just out of curiosity, as a hypothetical, if there was an enclosed area with a very slow ventilation system and a release of hydrogen sulfide, hydrogen cyanide, etc. (chemicals that kill your sense of smell), how long would you have to be outside the area before you could reenter and smell it again? Not looking for someone to test this one:), just curious and couldn't find any kind of info.
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macckone
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[*] posted on 5-12-2015 at 08:17


Both hydrogen cyanide and sulfide can kill your sense of smell. It may never fully recover. I think for recovery it is going to be very dependent on the individual, expose concentration and length of exposure. And like I said at the upper end you may never fully recover.
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diddi
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[*] posted on 5-12-2015 at 12:10


That's an experiment I am not will to try :(
People have commented on my very acute sense of smell, and I have bee exposed to chems for 35 years. Always pays to be careful.

[Edited on 5-12-2015 by diddi]




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[*] posted on 6-12-2015 at 06:16


You won't have to, it has been done.

Stuck B.A. et al (2013) Chemical Senses 39(2):151-157

http://chemse.oxfordjournals.org/content/39/2/151

Briefly scanning the paper 'diagonally' I think the brief answer is that the recovery time is concentration dependent and on the order of several minutes. But I could not be bothered to read it properly, so have a look for yourself if you are really interested.




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[*] posted on 6-12-2015 at 08:29


Quote: Originally posted by phlogiston  
You won't have to, it has been done.

Stuck B.A. et al (2013) Chemical Senses 39(2):151-157

http://chemse.oxfordjournals.org/content/39/2/151

Briefly scanning the paper 'diagonally' I think the brief answer is that the recovery time is concentration dependent and on the order of several minutes. But I could not be bothered to read it properly, so have a look for yourself if you are really interested.


Thanks for finding this.

The highest H2S concentration they tested was 8 ppm (lowest 2 ppm). For this full densensitization took from 40-110 sec (mean 70), some recovery after even 5 seconds and substantial recovery at sec. At these low concentrations the actual concentrations did not have any effect on the time for either process. Unfortunately this not provide much guidance for what happens at say, 100 ppm.

Olfactory desensitization is a general phenomenon, but H2S's ability to cause it is unusually pronounced.

I have never read anything to indicate desensitization by H2S or HCN is anything but temporary, unless perhaps actual gross poisoning occurs which is an entirely different matter.
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macckone
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[*] posted on 1-1-2016 at 11:34


Above 50ppm tissue damage can occur to the cornea. At 100ppm permanent damage to other tissue can occur. 350ppm is considered deadly. The usual level for alarms in industrial areas and plants is 10ppm.
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[*] posted on 1-1-2016 at 12:52


Being able to rely in other indicators, I would avoid to use the nose as a measuring instrument.
Look for "anosmia" in Wikipedia. The reduction or loss of sense of smell.
In my particular case, I discovered my reduction of this sense by comparison with fellows in the lab. This was by chance and I suspect I realized late.
May be my age, may be the exposure to different dangerous products from time to time or may be a combination of effects. Hard to tell...
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[*] posted on 1-1-2016 at 14:28


Years ago I talked with industrial chemists making bromoalkanes. They didn't smell it anymore and were habituated to them; not taking long vacations. The concentrations of H2S required to cause tissue damage are beyond the extinction concentration according to some geochemist friends. At those levels you'd be lucky to survive. A colleague was pulled from an active caldera and taken away by chopper to recover in ICU. He recovered; including the ability to smell H2S, He was unlucky with his harness but lucky with available helicopters.



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[*] posted on 4-1-2016 at 10:13


Quote: Originally posted by chemrox  
Years ago I talked with industrial chemists making bromoalkanes. They didn't smell it anymore and were habituated to them; not taking long vacations. The concentrations of H2S required to cause tissue damage are beyond the extinction concentration according to some geochemist friends. At those levels you'd be lucky to survive. A colleague was pulled from an active caldera and taken away by chopper to recover in ICU. He recovered; including the ability to smell H2S, He was unlucky with his harness but lucky with available helicopters.

The various points where tissue damage (50-100ppm) occur are well above the point of loss of ofactory perception (2ppm) but also well under the point of death(350ppm). In any case getting exposed above 10ppm on a regular basis seems like a bad idea although the data suggests perceptible tissue damage doesn't occur until a much higher level. Of course any individual is going to react differently so some hearty soul might be able to withstand 500pm without any long term effects but another person with asthma and copd might die at 1ppm. These values are estimated averages since we don't experiment on humans. Take them as you will and don't expose youself unnecessarily.
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[*] posted on 10-1-2016 at 13:23


Small concentrations also bring problems: headache, dizziness, fatigue, and irritation, besides the smell stick nostrils for weeks in some cases
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[*] posted on 10-1-2016 at 15:00


I once inhaled a lot of HCl and I can't smell it anymore, even 2 years later:o



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